This README file contains build instructions for the OpenJDK. Building the source code for the OpenJDK requires a certain degree of technical expertise.
-Some Headlines:
-configure && make" style buildvsvars*.bat and vcvars*.bat files are run automaticallyIf you are eager to try out building OpenJDK, these simple steps works most of the time. They assume that you have installed Mercurial (and Cygwin if running on Windows) and cloned the top-level OpenJDK repository that you want to build.
+Get the complete source code:
+bash get_source.sh
Run configure:
+bash configure
If configure fails due to missing dependencies (to either the toolchain, external libraries or the boot JDK), most of the time it prints a suggestion on how to resolve the situation on your platform. Follow the instructions, and try running bash configure again.
Run make:
+make images
Verify your newly built JDK:
+./build/*/images/jdk/bin/java -version
Run basic tests:
+make run-test-tier1
If any of these steps failed, or if you want to know more about build requirements or build functionality, please continue reading this document.
+OpenJDK is a complex software project. Building it requires a certain amount of technical expertise, a fair number of dependencies on external software, and reasonably powerful hardware.
+If you just want to use OpenJDK and not build it yourself, this document is not for you. See for instance OpenJDK installation for some methods of installing a prebuilt OpenJDK.
+OpenJDK uses Mercurial for source control. The source code is contained not in a single Mercurial repository, but in a tree ("forest") of interrelated repositories. You will need to check out all of the repositories to be able to build OpenJDK. To assist you in dealing with this somewhat unusual arrangement, there are multiple tools available, which are explained below.
+In any case, make sure you are getting the correct version. At the OpenJDK Mercurial server you can see a list of all available forests. If you want to build an older version, e.g. JDK 8, it is recommended that you get the jdk8u forest, which contains incremental updates, instead of the jdk8 forest, which was frozen at JDK 8 GA.
If you are new to Mercurial, a good place to start is the Mercurial Beginner's Guide. The rest of this document assumes a working knowledge of Mercurial.
+For a smooth building experience, it is recommended that you follow these rules on where and how to check out the source code.
Do not check out the source code in a path which contains spaces. Chances are the build will not work. This is most likely to be an issue on Windows systems.
Do not check out the source code in a path which has a very long name or is nested many levels deep. Chances are you will hit an OS limitation during the build.
Put the source code on a local disk, not a network share. If possible, use an SSD. The build process is very disk intensive, and having slow disk access will significantly increase build times. If you need to use a network share for the source code, see below for suggestions on how to keep the build artifacts on a local disk.
On Windows, extra care must be taken to make sure the Cygwin environment is consistent. It is recommended that you follow this procedure:
Create the directory that is going to contain the top directory of the OpenJDK clone by using the mkdir command in the Cygwin bash shell. That is, do not create it using Windows Explorer. This will ensure that it will have proper Cygwin attributes, and that it's children will inherit those attributes.
Do not put the OpenJDK clone in a path under your Cygwin home directory. This is especially important if your user name contains spaces and/or mixed upper and lower case letters.
Clone the OpenJDK repository using the Cygwin command line hg client as instructed in this document. That is, do not use another Mercurial client such as TortoiseHg.
Failure to follow this procedure might result in hard-to-debug build problems.
The simplest way to get the entire forest is probably to clone the top-level repository and then run the get_source.sh script, like this:
hg clone http://hg.openjdk.java.net/jdk9/jdk9
+cd jdk9
+bash get_source.shThe first time this is run, it will clone all the sub-repositories. Any subsequent execution of the script will update all sub-repositories to the latest revision.
+The hgforest.sh script is more expressive than get_source.sh. It takes any number of arguments, and runs hg with those arguments on each sub-repository in the forest. The get_source.sh script is basically a simple wrapper that runs either hgforest.sh clone or hgforest.sh pull -u.
Cloning the forest:
+hg clone http://hg.openjdk.java.net/jdk9/jdk9
+cd jdk9
+bash common/bin/hgforest.sh clonePulling and updating the forest:
+bash common/bin/hgforest.sh pull -uMerging over the entire forest:
+bash common/bin/hgforest.sh mergeThe OpenJDK sources are maintained with the revision control system Mercurial. If you are new to Mercurial, please see the Beginner Guides or refer to the Mercurial Book. The first few chapters of the book provide an excellent overview of Mercurial, what it is and how it works.
-For using Mercurial with the OpenJDK refer to the Developer Guide: Installing and Configuring Mercurial section for more information.
-To get the entire set of OpenJDK Mercurial repositories use the script get_source.sh located in the root repository:
hg clone http://hg.openjdk.java.net/jdk9/jdk9 YourOpenJDK
- cd YourOpenJDK
- bash ./get_source.shOnce you have all the repositories, keep in mind that each repository is its own independent repository. You can also re-run ./get_source.sh anytime to pull over all the latest changesets in all the repositories. This set of nested repositories has been given the term "forest" and there are various ways to apply the same hg command to each of the repositories. For example, the script make/scripts/hgforest.sh can be used to repeat the same hg command on every repository, e.g.
cd YourOpenJDK
- bash ./make/scripts/hgforest.sh statusThe set of repositories and what they contain:
+The trees extension is a Mercurial add-on that helps you deal with the forest. More information is available on the Code Tools trees page.
+Install the extension by cloning http://hg.openjdk.java.net/code-tools/trees and updating your .hgrc file. Here's one way to do this:
cd ~
+mkdir hg-ext
+cd hg-ext
+hg clone http://hg.openjdk.java.net/code-tools/trees
+cat << EOT >> ~/.hgrc
+[extensions]
+trees=~/hg-ext/trees/trees.py
+EOTThe trees extension needs to know the structure of the forest. If you have already cloned the entire forest using another method, you can initialize the forest like this:
+hg tconf --set --walk --depthOr you can clone the entire forest at once, if you substitute clone with tclone when cloning the top-level repository, e.g. like this:
hg tclone http://hg.openjdk.java.net/jdk9/jdk9In this case, the forest will be properly initialized from the start.
+The trees extensions supplement many common operations with a trees version by prefixing a t to the normal Mercurial command, e.g. tcommit, tstatus or tmerge. For instance, to update the entire forest:
hg tpull -uOpenJDK is a massive project, and require machines ranging from decent to powerful to be able to build in a reasonable amount of time, or to be able to complete a build at all.
+We strongly recommend usage of an SSD disk for the build, since disk speed is one of the limiting factors for build performance.
+At a minimum, a machine with 2-4 cores is advisable, as well as 2-4 GB of RAM. (The more cores to use, the more memory you need.) At least 6 GB of free disk space is required (8 GB minimum for building on Solaris).
+Even for 32-bit builds, it is recommended to use a 64-bit build machine, and instead create a 32-bit target using --with-target-bits=32.
At a minimum, a machine with 4 cores is advisable, as well as 4 GB of RAM. (The more cores to use, the more memory you need.) At least 8 GB of free disk space is required.
+This is not recommended. Instead, see the section on Cross-compiling.
+The mainline OpenJDK project supports Linux, Solaris, macOS, AIX and Windows. Support for other operating system, e.g. BSD, exists in separate "port" projects.
+In general, OpenJDK can be built on a wide range of versions of these operating systems, but the further you deviate from what is tested on a daily basis, the more likely you are to run into problems.
+This table lists the OS versions used by Oracle when building JDK 9. Such information is always subject to change, but this table is up to date at the time of writing.
+| Operating system | +Vendor/version used | +
|---|---|
| Linux | +Oracle Enterprise Linux 6.4 / 7.1 (using kernel 3.8.13) | +
| Solaris | +Solaris 11.1 SRU 21.4.1 / 11.2 SRU 5.5 | +
| macOS | +Mac OS X 10.9 (Mavericks) / 10.10 (Yosemite) | +
| Windows | +Windows Server 2012 R2 | +
The double version numbers for Linux, Solaris and macOS is due to the hybrid model used at Oracle, where header files and external libraries from an older version is used when building on a more modern version of the OS.
+The Build Group has a wiki page with Supported Build Platforms. From time to time, this is updated by the community to list successes or failures of building on different platforms.
+Windows XP is not a supported platform, but all newer Windows should be able to build OpenJDK.
+On Windows, it is important that you pay attention to the instructions in the Special Considerations.
+Windows is the only non-POSIX OS supported by OpenJDK, and as such, requires some extra care. A POSIX support layer is required to build on Windows. For OpenJDK 9, the only supported such layer is Cygwin. (Msys is no longer supported due to a too old bash; msys2 and the new Windows Subsystem for Linux (WSL) would likely be possible to support in a future version but that would require a community effort to implement.)
+Internally in the build system, all paths are represented as Unix-style paths, e.g. /cygdrive/c/hg/jdk9/Makefile rather than C:\hg\jdk9\Makefile. This rule also applies to input to the build system, e.g. in arguments to configure. So, use --with-freetype=/cygdrive/c/freetype rather than --with-freetype=c:\freetype. For details on this conversion, see the section on Fixpath.
A functioning Cygwin environment is thus required for building OpenJDK on Windows. If you have a 64-bit OS, we strongly recommend using the 64-bit version of Cygwin.
+Note: Cygwin has a model of continuously updating all packages without any easy way to install or revert to a specific version of a package. This means that whenever you add or update a package in Cygwin, you might (inadvertently) update tools that are used by the OpenJDK build process, and that can cause unexpected build problems.
+OpenJDK requires GNU Make 4.0 or greater on Windows. This is usually not a problem, since Cygwin currently only distributes GNU Make at a version above 4.0.
+Apart from the basic Cygwin installation, the following packages must also be installed:
There are some very basic guidelines:
-build/ directory..hgignore file in each repository must exist and should include ^build/, ^dist/ and optionally any nbproject/private directories. It should NEVER include anything in the src/ or test/ or any managed directory area of a repository.javah output). There are some exceptions to this rule, in particular with some of the generated configure scripts.makezipunzipThe very first step in building the OpenJDK is making sure the system itself has everything it needs to do OpenJDK builds. Once a system is setup, it generally doesn't need to be done again.
-Building the OpenJDK is now done with running a configure script which will try and find and verify you have everything you need, followed by running make, e.g.
---
bash ./configure
-make all
Where possible the configure script will attempt to located the various components in the default locations or via component specific variable settings. When the normal defaults fail or components cannot be found, additional configure options may be necessary to help configure find the necessary tools for the build, or you may need to re-visit the setup of your system due to missing software packages.
NOTE: The configure script file does not have execute permissions and will need to be explicitly run with bash, see the source guidelines.
Before even attempting to use a system to build the OpenJDK there are some very basic system setups needed. For all systems:
-make -version"* Install a Bootstrap JDK. All OpenJDK builds require access to a previously released JDK called the bootstrap JDK or boot JDK. The general rule is that the bootstrap JDK must be an instance of the previous major release of the JDK. In addition, there may be a requirement to use a release at or beyond a particular update level.
-Building JDK 9 requires JDK 8. JDK 9 developers should not use JDK 9 as the boot JDK, to ensure that JDK 9 dependencies are not introduced into the parts of the system that are built with JDK 8.
-The JDK 8 binaries can be downloaded from Oracle's JDK 8 download site. For build performance reasons it is very important that this bootstrap JDK be made available on the local disk of the machine doing the build. You should add its bin directory to the PATH environment variable. If configure has any issues finding this JDK, you may need to use the configure option --with-boot-jdk.
And for specific systems:
-Install all the software development packages needed including alsa, freetype, cups, and xrender. See specific system packages.
-Install all the software development packages needed including Studio Compilers, freetype, cups, and xrender. See specific system packages.
-Windows
Install Visual Studio 2013
Mac OS X
Install XCode 6.3
-With Linux, try and favor the system packages over building your own or getting packages from other areas. Most Linux builds should be possible with the system's available packages.
-Note that some Linux systems have a habit of pre-populating your environment variables for you, for example JAVA_HOME might get pre-defined for you to refer to the JDK installed on your Linux system. You will need to unset JAVA_HOME. It's a good idea to run env and verify the environment variables you are getting from the default system settings make sense for building the OpenJDK.
At a minimum, the Studio 12 Update 4 Compilers (containing version 5.13 of the C and C++ compilers) is required, including specific patches.
+Often, you can install these packages using the following command line:
+<path to Cygwin setup>/setup-x86_64 -q -P make -P unzip -P zipUnfortunately, Cygwin can be unreliable in certain circumstances. If you experience build tool crashes or strange issues when building on Windows, please check the Cygwin FAQ on the "BLODA" list and the section on fork() failures.
+See make/devkit/solaris11.1-package-list.txt for a list of recommended packages to install when building on Solaris. The versions specified in this list is the versions used by the daily builds at Oracle, and is likely to work properly.
Older versions of Solaris shipped a broken version of objcopy. At least version 2.21.1 is needed, which is provided by Solaris 11 Update 1. Objcopy is needed if you want to have external debug symbols. Please make sure you are using at least version 2.21.1 of objcopy, or that you disable external debug symbols.
Apple is using a quite aggressive scheme of pushing OS updates, and coupling these updates with required updates of Xcode. Unfortunately, this makes it difficult for a project like OpenJDK to keep pace with a continuously updated machine running macOS. See the section on Apple Xcode on some strategies to deal with this.
+It is recommended that you use at least Mac OS X 10.9 (Mavericks). At the time of writing, OpenJDK has been successfully compiled on macOS versions up to 10.12.5 (Sierra), using XCode 8.3.2 and --disable-warnings-as-errors.
The standard macOS environment contains the basic tooling needed to build, but for external libraries a package manager is recommended. OpenJDK uses homebrew in the examples, but feel free to use whatever manager you want (or none).
+It is often not much problem to build OpenJDK on Linux. The only general advice is to try to use the compilers, external libraries and header files as provided by your distribution.
+The basic tooling is provided as part of the core operating system, but you will most likely need to install developer packages.
+For apt-based distributions (Debian, Ubuntu, etc), try this:
+sudo apt-get install build-essentialFor rpm-based distributions (Fedora, Red Hat, etc), try this:
+sudo yum groupinstall "Development Tools"The regular builds by SAP is using AIX version 7.1, but AIX 5.3 is also supported. See the OpenJDK PowerPC Port Status Page for details.
+Large portions of OpenJDK consists of native code, that needs to be compiled to be able to run on the target platform. In theory, toolchain and operating system should be independent factors, but in practice there's more or less a one-to-one correlation between target operating system and toolchain.
+| Operating system | +Supported toolchain | +
|---|---|
| Linux | +gcc, clang | +
| macOS | +Apple Xcode (using clang) | +
| Solaris | +Oracle Solaris Studio | +
| AIX | +IBM XL C/C++ | +
| Windows | +Microsoft Visual Studio | +
Please see the individual sections on the toolchains for version recommendations. As a reference, these versions of the toolchains are used, at the time of writing, by Oracle for the daily builds of OpenJDK. It should be possible to compile OpenJDK with both older and newer versions, but the closer you stay to this list, the more likely you are to compile successfully without issues.
+| Operating system | +Toolchain version | +
|---|---|
| Linux | +gcc 4.9.2 | +
| macOS | +Apple Xcode 6.3 (using clang 6.1.0) | +
| Solaris | +Oracle Solaris Studio 12.4 (with compiler version 5.13) | +
| Windows | +Microsoft Visual Studio 2013 update 4 | +
The minimum accepted version of gcc is 4.3. Older versions will not be accepted by configure.
However, gcc 4.3 is quite old and OpenJDK is not regularly tested on this version, so it is recommended to use a more modern gcc.
+OpenJDK 9 includes patches that should allow gcc 6 to compile, but this should be considered experimental.
+In general, any version between these two should be usable.
+The minimum accepted version of clang is 3.2. Older versions will not be accepted by configure.
To use clang instead of gcc on Linux, use --with-toolchain-type=clang.
The oldest supported version of Xcode is 5.
+You will need the Xcode command lines developers tools to be able to build OpenJDK. (Actually, only the command lines tools are needed, not the IDE.) The simplest way to install these is to run:
+xcode-select --installIt is advisable to keep an older version of Xcode for building OpenJDK when updating Xcode. This blog page has good suggestions on managing multiple Xcode versions. To use a specific version of Xcode, use xcode-select -s before running configure, or use --with-toolchain-path to point to the version of Xcode to use, e.g. configure --with-toolchain-path=/Applications/Xcode5.app/Contents/Developer/usr/bin
If you have recently (inadvertently) updated your OS and/or Xcode version, and OpenJDK can no longer be built, please see the section on Problems with the Build Environment, and Getting Help to find out if there are any recent, non-merged patches available for this update.
+The minimum accepted version of the Solaris Studio compilers is 5.13 (corresponding to Solaris Studio 12.4). Older versions will not be accepted by configure.
The Solaris Studio installation should contain at least these packages:
In particular backend 12.4-1.0.6.0 contains a critical patch for the sparc version.
-Place the bin directory in PATH.
The Oracle Solaris Studio Express compilers at: Oracle Solaris Studio Express Download site are also an option, although these compilers have not been extensively used yet.
-Building on Windows requires a Unix-like environment, notably a Unix-like shell. There are several such environments available of which Cygwin and MinGW/MSYS are currently supported for the OpenJDK build. One of the differences of these systems from standard Windows tools is the way they handle Windows path names, particularly path names which contain spaces, backslashes as path separators and possibly drive letters. Depending on the use case and the specifics of each environment these path problems can be solved by a combination of quoting whole paths, translating backslashes to forward slashes, escaping backslashes with additional backslashes and translating the path names to their "8.3" version.
-CYGWIN is an open source, Linux-like environment which tries to emulate a complete POSIX layer on Windows. It tries to be smart about path names and can usually handle all kinds of paths if they are correctly quoted or escaped although internally it maps drive letters <drive>: to a virtual directory /cygdrive/<drive>.
You can always use the cygpath utility to map pathnames with spaces or the backslash character into the C:/ style of pathname (called 'mixed'), e.g. cygpath -s -m "<path>".
Note that the use of CYGWIN creates a unique problem with regards to setting PATH. Normally on Windows the PATH variable contains directories separated with the ";" character (Solaris and Linux use ":"). With CYGWIN, it uses ":", but that means that paths like "C:/path" cannot be placed in the CYGWIN version of PATH and instead CYGWIN uses something like /cygdrive/c/path which CYGWIN understands, but only CYGWIN understands.
The OpenJDK build requires CYGWIN version 1.7.16 or newer. Information about CYGWIN can be obtained from the CYGWIN website at www.cygwin.com.
-By default CYGWIN doesn't install all the tools required for building the OpenJDK. Along with the default installation, you need to install the following tools.
-| Binary Name | -Category | -Package | -Description | -
|---|---|---|---|
| ar.exe | -Devel | -binutils | -The GNU assembler, linker and binary utilities | -
| make.exe | -Devel | -make | -The GNU version of the 'make' utility built for CYGWIN | -
| m4.exe | -Interpreters | -m4 | -GNU implementation of the traditional Unix macro processor | -
| cpio.exe | -Utils | -cpio | -A program to manage archives of files | -
| gawk.exe | -Utils | -awk | -Pattern-directed scanning and processing language | -
| file.exe | -Utils | -file | -Determines file type using 'magic' numbers | -
| zip.exe | -Archive | -zip | -Package and compress (archive) files | -
| unzip.exe | -Archive | -unzip | -Extract compressed files in a ZIP archive | -
| free.exe | -System | -procps | -Display amount of free and used memory in the system | -
Note that the CYGWIN software can conflict with other non-CYGWIN software on your Windows system. CYGWIN provides a FAQ for known issues and problems, of particular interest is the section on BLODA (applications that interfere with CYGWIN).
-MinGW ("Minimalist GNU for Windows") is a collection of free Windows specific header files and import libraries combined with GNU toolsets that allow one to produce native Windows programs that do not rely on any 3rd-party C runtime DLLs. MSYS is a supplement to MinGW which allows building applications and programs which rely on traditional UNIX tools to be present. Among others this includes tools like bash and make. See MinGW/MSYS for more information.
Like Cygwin, MinGW/MSYS can handle different types of path formats. They are internally converted to paths with forward slashes and drive letters <drive>: replaced by a virtual directory /<drive>. Additionally, MSYS automatically detects binaries compiled for the MSYS environment and feeds them with the internal, Unix-style path names. If native Windows applications are called from within MSYS programs their path arguments are automatically converted back to Windows style path names with drive letters and backslashes as path separators. This may cause problems for Windows applications which use forward slashes as parameter separator (e.g. cl /nologo /I) because MSYS may wrongly replace such parameters by drive letters.
In addition to the tools which will be installed by default, you have to manually install the msys-zip and msys-unzip packages. This can be easily done with the MinGW command line installer:
mingw-get.exe install msys-zip
- mingw-get.exe install msys-unzipThe 32-bit and 64-bit OpenJDK Windows build requires Microsoft Visual Studio C++ 2013 (VS2013) Professional Edition or Express compiler. The compiler and other tools are expected to reside in the location defined by the variable VS120COMNTOOLS which is set by the Microsoft Visual Studio installer.
Only the C++ part of VS2013 is needed. Try to let the installation go to the default install directory. Always reboot your system after installing VS2013. The system environment variable VS120COMNTOOLS should be set in your environment.
-Make sure that TMP and TEMP are also set in the environment and refer to Windows paths that exist, like C:\temp, not /tmp, not /cygdrive/c/temp, and not C:/temp. C:\temp is just an example, it is assumed that this area is private to the user, so by default after installs you should see a unique user path in these variables.
Make sure you get the right XCode version.
-The basic invocation of the configure script looks like:
---
bash ./configure [options]
This will create an output directory containing the "configuration" and setup an area for the build result. This directory typically looks like:
----
build/linux-x64-normal-server-release
configure will try to figure out what system you are running on and where all necessary build components are. If you have all prerequisites for building installed, it should find everything. If it fails to detect any component automatically, it will exit and inform you about the problem. When this happens, read more below in the configure options.
Some examples:
---Windows 32bit build with freetype specified:
-
-bash ./configure --with-freetype=/cygdrive/c/freetype-i586 --with-target-bits=32
--Debug 64bit Build:
-
-bash ./configure --enable-debug --with-target-bits=64
Complete details on all the OpenJDK configure options can be seen with:
---
bash ./configure --help=short
Use -help to see all the configure options available. You can generate any number of different configurations, e.g. debug, release, 32, 64, etc.
Some of the more commonly used configure options are:
-- --
--enable-debug
-set the debug level to fastdebug (this is a shorthand for--with-debug-level=fastdebug)
---
--with-alsa=path
-select the location of the Advanced Linux Sound Architecture (ALSA)
--Version 0.9.1 or newer of the ALSA files are required for building the OpenJDK on Linux. These Linux files are usually available from an "alsa" of "libasound" development package, and it's highly recommended that you try and use the package provided by the particular version of Linux that you are using.
-
---
--with-boot-jdk=path
-select the Bootstrap JDK
---
--with-boot-jdk-jvmargs="args"
-provide the JVM options to be used to run the Bootstrap JDK
---
--with-cacerts=path
-select the path to the cacerts file.
-- -See Certificate Authority on Wikipedia for a better understanding of the Certificate Authority (CA). A certificates file named "cacerts" represents a system-wide keystore with CA certificates. In JDK and JRE binary bundles, the "cacerts" file contains root CA certificates from several public CAs (e.g., VeriSign, Thawte, and Baltimore). The source contain a cacerts file without CA root certificates. Formal JDK builders will need to secure permission from each public CA and include the certificates into their own custom cacerts file. Failure to provide a populated cacerts file will result in verification errors of a certificate chain during runtime. By default an empty cacerts file is provided and that should be fine for most JDK developers.
-
---
--with-cups=path
-select the CUPS install location
--The Common UNIX Printing System (CUPS) Headers are required for building the OpenJDK on Solaris and Linux. The Solaris header files can be obtained by installing the package print/cups.
-
--The CUPS header files can always be downloaded from www.cups.org.
-
---
--with-cups-include=path
-select the CUPS include directory location
---
--with-debug-level=level
-select the debug information level of release, fastdebug, or slowdebug
-- --
--with-dev-kit=path
-select location of the compiler install or developer install location
---
--with-freetype=path
-select the freetype files to use.
--Expecting the freetype libraries under
-lib/and the headers underinclude/.
--Version 2.3 or newer of FreeType is required. On Unix systems required files can be available as part of your distribution (while you still may need to upgrade them). Note that you need development version of package that includes both the FreeType library and header files.
-
--You can always download latest FreeType version from the FreeType website. Building the freetype 2 libraries from scratch is also possible, however on Windows refer to the Windows FreeType DLL build instructions.
-
--Note that by default FreeType is built with byte code hinting support disabled due to licensing restrictions. In this case, text appearance and metrics are expected to differ from Sun's official JDK build. See the SourceForge FreeType2 Home Page for more information.
-
---
--with-import-hotspot=path
-select the location to find hotspot binaries from a previous build to avoid building hotspot
---
--with-target-bits=arg
-select 32 or 64 bit build
---
--with-jvm-variants=variants
-select the JVM variants to build from, comma separated list that can include: server, client, kernel, zero and zeroshark
---
--with-memory-size=size
-select the RAM size that GNU make will think this system has
---
--with-msvcr-dll=path
-select themsvcr100.dllfile to include in the Windows builds (C/C++ runtime library for Visual Studio).
--This is usually picked up automatically from the redist directories of Visual Studio 2013.
-
-- --
--with-num-cores=cores
-select the number of cores to use (processor count or CPU count)
---
--with-x=path
-select the location of the X11 and xrender files.
--The XRender Extension Headers are required for building the OpenJDK on Solaris and Linux. The Linux header files are usually available from a "Xrender" development package, it's recommended that you try and use the package provided by the particular distribution of Linux that you are using. The Solaris XRender header files is included with the other X11 header files in the package SFWxwinc on new enough versions of Solaris and will be installed in
-/usr/X11/include/X11/extensions/Xrender.hor/usr/openwin/share/include/X11/extensions/Xrender.h
The basic invocation of the make utility looks like:
---
make all
This will start the build to the output directory containing the "configuration" that was created by the configure script. Run make help for more information on the available targets.
There are some of the make targets that are of general interest:
---empty
-
-build everything but no images
---
all
-build everything including images
---
all-conf
-build all configurations
---
images
-create complete j2sdk and j2re images
---
install
-install the generated images locally, typically in/usr/local
---
clean
-remove all files generated by make, but not those generated byconfigure
---
dist-clean
-remove all files generated by both andconfigure(basically killing the configuration)
---
help
-give some help on usingmake, including some interesting make targets
When the build is completed, you should see the generated binaries and associated files in the j2sdk-image directory in the output directory. In particular, the build/*/images/j2sdk-image/bin directory should contain executables for the OpenJDK tools and utilities for that configuration. The testing tool jtreg will be needed and can be found at: the jtreg site. The provided regression tests in the repositories can be run with the command:
---
cd test && make PRODUCT_HOME=`pwd`/../build/*/images/j2sdk-image all
Q: The generated-configure.sh file looks horrible! How are you going to edit it?
-A: The generated-configure.sh file is generated (think "compiled") by the autoconf tools. The source code is in configure.ac and various .m4 files in common/autoconf, which are much more readable.
Q: Why is the generated-configure.sh file checked in, if it is generated?
-A: If it was not generated, every user would need to have the autoconf tools installed, and re-generate the configure file as the first step. Our goal is to minimize the work needed to be done by the user to start building OpenJDK, and to minimize the number of external dependencies required.
Q: Do you require a specific version of autoconf for regenerating generated-configure.sh?
-A: Yes, version 2.69 is required and should be easy enough to aquire on all supported operating systems. The reason for this is to avoid large spurious changes in generated-configure.sh.
Q: How do you regenerate generated-configure.sh after making changes to the input files?
-A: Regnerating generated-configure.sh should always be done using the script common/autoconf/autogen.sh to ensure that the correct files get updated. This script should also be run after mercurial tries to merge generated-configure.sh as a merge of the generated file is not guaranteed to be correct.
Q: What are the files in common/makefiles/support/* for? They look like gibberish.
-A: They are a somewhat ugly hack to compensate for command line length limitations on certain platforms (Windows, Solaris). Due to a combination of limitations in make and the shell, command lines containing too many files will not work properly. These helper files are part of an elaborate hack that will compress the command line in the makefile and then uncompress it safely. We're not proud of it, but it does fix the problem. If you have any better suggestions, we're all ears! :-)
Q: I want to see the output of the commands that make runs, like in the old build. How do I do that?
-A: You specify the LOG variable to make. There are several log levels:
Compiling with Solaris Studio can sometimes be finicky. This is the exact version used by Oracle, which worked correctly at the time of writing:
+$ cc -V
+cc: Sun C 5.13 SunOS_i386 2014/10/20
+$ CC -V
+CC: Sun C++ 5.13 SunOS_i386 151846-10 2015/10/30The minimum accepted version of Visual Studio is 2010. Older versions will not be accepted by configure. The maximum accepted version of Visual Studio is 2013.
If you have multiple versions of Visual Studio installed, configure will by default pick the latest. You can request a specific version to be used by setting --with-toolchain-version, e.g. --with-toolchain-version=2010.
If you get LINK: fatal error LNK1123: failure during conversion to COFF: file invalid when building using Visual Studio 2010, you have encountered KB2757355, a bug triggered by a specific installation order. However, the solution suggested by the KB article does not always resolve the problem. See this stackoverflow discussion for other suggestions.
The regular builds by SAP is using version 12.1, described as IBM XL C/C++ for AIX, V12.1 (5765-J02, 5725-C72) Version: 12.01.0000.0017.
See the OpenJDK PowerPC Port Status Page for details.
+Paradoxically, building OpenJDK requires a pre-existing JDK. This is called the "boot JDK". The boot JDK does not have to be OpenJDK, though. If you are porting OpenJDK to a new platform, chances are that there already exists another JDK for that platform that is usable as boot JDK.
+The rule of thumb is that the boot JDK for building JDK major version N should be an JDK of major version N-1, so for building JDK 9 a JDK 8 would be suitable as boot JDK. However, OpenJDK should be able to "build itself", so an up-to-date build of the current OpenJDK source is an acceptable alternative. If you are following the N-1 rule, make sure you got the latest update version, since JDK 8 GA might not be able to build JDK 9 on all platforms.
+If the Boot JDK is not automatically detected, or the wrong JDK is picked, use --with-boot-jdk to point to the JDK to use.
On apt-based distros (like Debian and Ubuntu), sudo apt-get install openjdk-8-jdk is typically enough to install OpenJDK 8. On rpm-based distros (like Fedora and Red Hat), try sudo yum install java-1.8.0-openjdk-devel.
No pre-compiled binaries of OpenJDK 8 are readily available for Windows at the time of writing. An alternative is to download the Oracle JDK. Another is the Adopt OpenJDK Project, which publishes experimental prebuilt binaries for Windows.
+No pre-compiled binaries of OpenJDK 8 are readily available for macOS at the time of writing. An alternative is to download the Oracle JDK, or to install it using brew cask install java. Another option is the Adopt OpenJDK Project, which publishes experimental prebuilt binaries for macOS.
No pre-compiled binaries of OpenJDK 8 are readily available for AIX at the time of writing. A starting point for working with OpenJDK on AIX is the PowerPC/AIX Port Project.
+Different platforms require different external libraries. In general, libraries are not optional - that is, they are either required or not used.
+If a required library is not detected by configure, you need to provide the path to it. There are two forms of the configure arguments to point to an external library: --with-<LIB>=<path> or --with-<LIB>-include=<path to include> --with-<LIB>-lib=<path to lib>. The first variant is more concise, but require the include files an library files to reside in a default hierarchy under this directory. In most cases, it works fine.
As a fallback, the second version allows you to point to the include directory and the lib directory separately.
+FreeType2 from The FreeType Project is required on all platforms. At least version 2.3 is required.
+sudo apt-get install libcups2-dev.sudo yum install cups-devel.pkg install system/library/freetype-2.brew install freetype.Use --with-freetype=<path> if configure does not properly locate your FreeType files.
On Windows, there is no readily available compiled version of FreeType. OpenJDK can help you compile FreeType from source. Download the FreeType sources and unpack them into an arbitrary directory:
+wget http://download.savannah.gnu.org/releases/freetype/freetype-2.5.3.tar.gz
+tar -xzf freetype-2.5.3.tar.gzThen run configure with --with-freetype-src=<freetype_src>. This will automatically build the freetype library into <freetype_src>/lib64 for 64-bit builds or into <freetype_src>/lib32 for 32-bit builds. Afterwards you can always use --with-freetype-include=<freetype_src>/include and --with-freetype-lib=<freetype_src>/lib[32|64] for other builds.
Alternatively you can unpack the sources like this to use the default directory:
+tar --one-top-level=$HOME/freetype --strip-components=1 -xzf freetype-2.5.3.tar.gzCUPS, Common UNIX Printing System header files are required on all platforms, except Windows. Often these files are provided by your operating system.
+sudo apt-get install libcups2-dev.sudo yum install cups-devel.pkg install print/cups.Use --with-cups=<path> if configure does not properly locate your CUPS files.
Certain X11 libraries and include files are required on Linux and Solaris.
+sudo apt-get install libx11-dev libxext-dev libxrender-dev libxtst-dev libxt-dev.sudo yum install libXtst-devel libXt-devel libXrender-devel libXi-devel.pkg install x11/header/x11-protocols x11/library/libice x11/library/libpthread-stubs x11/library/libsm x11/library/libx11 x11/library/libxau x11/library/libxcb x11/library/libxdmcp x11/library/libxevie x11/library/libxext x11/library/libxrender x11/library/libxscrnsaver x11/library/libxtst x11/library/toolkit/libxt.Use --with-x=<path> if configure does not properly locate your X11 files.
ALSA, Advanced Linux Sound Architecture is required on Linux. At least version 0.9.1 of ALSA is required.
+sudo apt-get install libasound2-dev.sudo yum install alsa-lib-devel.Use --with-alsa=<path> if configure does not properly locate your ALSA files.
libffi, the Portable Foreign Function Interface Library is required when building the Zero version of Hotspot.
+sudo apt-get install libffi-dev.sudo yum install libffi-devel.Use --with-libffi=<path> if configure does not properly locate your libffi files.
libelf from the elfutils project is required when building the AOT feature of Hotspot.
+sudo apt-get install libelf-dev.sudo yum install elfutils-libelf-devel.Use --with-libelf=<path> if configure does not properly locate your libelf files.
OpenJDK requires GNU Make. No other flavors of make are supported.
+At least version 3.81 of GNU Make must be used. For distributions supporting GNU Make 4.0 or above, we strongly recommend it. GNU Make 4.0 contains useful functionality to handle parallel building (supported by --with-output-sync) and speed and stability improvements.
Note that configure locates and verifies a properly functioning version of make and stores the path to this make binary in the configuration. If you start a build using make on the command line, you will be using the version of make found first in your PATH, and not necessarily the one stored in the configuration. This initial make will be used as "bootstrap make", and in a second stage, the make located by configure will be called. Normally, this will present no issues, but if you have a very old make, or a non-GNU Make make in your path, this might cause issues.
If you want to override the default make found by configure, use the MAKE configure variable, e.g. configure MAKE=/opt/gnu/make.
On Solaris, it is common to call the GNU version of make by using gmake.
OpenJDK requires GNU Bash. No other shells are supported.
+At least version 3.2 of GNU Bash must be used.
+If you want to modify the build system itself, you need to install Autoconf.
+However, if you only need to build OpenJDK or if you only edit the actual OpenJDK source files, there is no dependency on autoconf, since the source distribution includes a pre-generated configure shell script.
See the section on Autoconf Details for details on how OpenJDK uses autoconf. This is especially important if you plan to contribute changes to OpenJDK that modifies the build system.
+To build OpenJDK, you need a "configuration", which consists of a directory where to store the build output, coupled with information about the platform, the specific build machine, and choices that affect how OpenJDK is built.
+The configuration is created by the configure script. The basic invocation of the configure script looks like this:
bash configure [options]This will create an output directory containing the configuration and setup an area for the build result. This directory typically looks like build/linux-x64-normal-server-release, but the actual name depends on your specific configuration. (It can also be set directly, see Using Multiple Configurations). This directory is referred to as $BUILD in this documentation.
configure will try to figure out what system you are running on and where all necessary build components are. If you have all prerequisites for building installed, it should find everything. If it fails to detect any component automatically, it will exit and inform you about the problem.
Some command line examples:
+Create a 32-bit build for Windows with FreeType2 in C:\freetype-i586:
bash configure --with-freetype=/cygdrive/c/freetype-i586 --with-target-bits=32Create a debug build with the server JVM and DTrace enabled:
bash configure --enable-debug --with-jvm-variants=server --enable-dtraceHere follows some of the most common and important configure argument.
To get up-to-date information on all available configure argument, please run:
bash configure --help(Note that this help text also include general autoconf options, like --dvidir, that is not relevant to OpenJDK. To list only OpenJDK specific features, use bash configure --help=short instead.)
--enable-debug - Set the debug level to fastdebug (this is a shorthand for --with-debug-level=fastdebug)--with-debug-level=<level> - Set the debug level, which can be release, fastdebug, slowdebug or optimized. Default is release. optimized is variant of release with additional Hotspot debug code.--with-native-debug-symbols=<method> - Specify if and how native debug symbols should be built. Available methods are none, internal, external, zipped. Default behavior depends on platform. See Native Debug Symbols for more details.--with-version-string=<string> - Specify the version string this build will be identified with.--with-version-<part>=<value> - A group of options, where <part> can be any of pre, opt, build, major, minor, security or patch. Use these options to modify just the corresponding part of the version string from the default, or the value provided by --with-version-string.--with-jvm-variants=<variant>[,<variant>...] - Build the specified variant (or variants) of Hotspot. Valid variants are: server, client, minimal, core, zero, zeroshark, custom. Note that not all variants are possible to combine in a single build.--with-jvm-features=<feature>[,<feature>...] - Use the specified JVM features when building Hotspot. The list of features will be enabled on top of the default list. For the custom JVM variant, this default list is empty. A complete list of available JVM features can be found using bash configure --help.--with-target-bits=<bits> - Create a target binary suitable for running on a <bits> platform. Use this to create 32-bit output on a 64-bit build platform, instead of doing a full cross-compile. (This is known as a reduced build.)--with-devkit=<path> - Use this devkit for compilers, tools and resources--with-sysroot=<path> - Use this directory as sysroot--with-extra-path=<path>[;<path>] - Prepend these directories to the default path when searching for all kinds of binaries--with-toolchain-path=<path>[;<path>] - Prepend these directories when searching for toolchain binaries (compilers etc)--with-extra-cflags=<flags> - Append these flags when compiling JDK C files--with-extra-cxxflags=<flags> - Append these flags when compiling JDK C++ files--with-extra-ldflags=<flags> - Append these flags when linking JDK libraries--with-boot-jdk=<path> - Set the path to the Boot JDK--with-freetype=<path> - Set the path to FreeType--with-cups=<path> - Set the path to CUPS--with-x=<path> - Set the path to X11--with-alsa=<path> - Set the path to ALSA--with-libffi=<path> - Set the path to libffi--with-libelf=<path> - Set the path to libelf--with-jtreg=<path> - Set the path to JTReg. See Running TestsCertain third-party libraries used by OpenJDK (libjpeg, giflib, libpng, lcms and zlib) are included in the OpenJDK repository. The default behavior of the OpenJDK build is to use this version of these libraries, but they might be replaced by an external version. To do so, specify system as the <source> option in these arguments. (The default is bundled).
warn -- Default and very quiet.info -- Shows more progress information than warn.debug -- Echos all command lines and prints all macro calls for compilation definitions.trace -- Echos all $(shell) command lines as well.--with-libjpeg=<source> - Use the specified source for libjpeg--with-giflib=<source> - Use the specified source for giflib--with-libpng=<source> - Use the specified source for libpng--with-lcms=<source> - Use the specified source for lcms--with-zlib=<source> - Use the specified source for zlibOn Linux, it is possible to select either static or dynamic linking of the C++ runtime. The default is static linking, with dynamic linking as fallback if the static library is not found.
+--with-stdc++lib=<method> - Use the specified method (static, dynamic or default) for linking the C++ runtime.It is possible to control certain aspects of configure by overriding the value of configure variables, either on the command line or in the environment.
Normally, this is not recommended. If used improperly, it can lead to a broken configuration. Unless you're well versed in the build system, this is hard to use properly. Therefore, configure will print a warning if this is detected.
However, there are a few configure variables, known as control variables that are supposed to be overriden on the command line. These are variables that describe the location of tools needed by the build, like MAKE or GREP. If any such variable is specified, configure will use that value instead of trying to autodetect the tool. For instance, bash configure MAKE=/opt/gnumake4.0/bin/make.
If a configure argument exists, use that instead, e.g. use --with-jtreg instead of setting JTREGEXE.
Also note that, despite what autoconf claims, setting CFLAGS will not accomplish anything. Instead use --with-extra-cflags (and similar for cxxflags and ldflags).
When you have a proper configuration, all you need to do to build OpenJDK is to run make. (But see the warning at GNU Make about running the correct version of make.)
When running make without any arguments, the default target is used, which is the same as running make default or make jdk. This will build a minimal (or roughly minimal) set of compiled output (known as an "exploded image") needed for a developer to actually execute the newly built JDK. The idea is that in an incremental development fashion, when doing a normal make, you should only spend time recompiling what's changed (making it purely incremental) and only do the work that's needed to actually run and test your code.
The output of the exploded image resides in $BUILD/jdk. You can test the newly built JDK like this: $BUILD/jdk/bin/java -version.
Apart from the default target, here are some common make targets:
+hotspot - Build all of hotspot (but only hotspot)hotspot-<variant> - Build just the specified jvm variantimages or product-images - Build the JRE and JDK imagesdocs or docs-image - Build the documentation imagetest-image - Build the test imageall or all-images - Build all images (product, docs and test)bootcycle-images - Build images twice, second time with newly built JDK (good for testing)clean - Remove all files generated by make, but not those generated by configuredist-clean - Remove all files, including configurationRun make help to get an up-to-date list of important make targets and make control variables.
It is possible to build just a single module, a single phase, or a single phase of a single module, by creating make targets according to these followin patterns. A phase can be either of gensrc, gendata, copy, java, launchers, libs or rmic. See Using Fine-Grained Make Targets for more details about this functionality.
<phase> - Build the specified phase and everything it depends on<module> - Build the specified module and everything it depends on<module>-<phase> - Compile the specified phase for the specified module and everything it depends onSimilarly, it is possible to clean just a part of the build by creating make targets according to these patterns:
+clean-<outputdir> - Remove the subdir in the output dir with the nameclean-<phase> - Remove all build results related to a certain build phaseclean-<module> - Remove all build results related to a certain moduleclean-<module>-<phase> - Remove all build results related to a certain module and phaseIt is possible to control make behavior by overriding the value of make variables, either on the command line or in the environment.
Normally, this is not recommended. If used improperly, it can lead to a broken build. Unless you're well versed in the build system, this is hard to use properly. Therefore, make will print a warning if this is detected.
However, there are a few make variables, known as control variables that are supposed to be overriden on the command line. These make up the "make time" configuration, as opposed to the "configure time" configuration.
JOBS - Specify the number of jobs to build with. See Build Performance.LOG - Specify the logging level and functionality. See Checking the Build Log FileCONF and CONF_NAME - Selecting the configuration(s) to use. See Using Multiple ConfigurationsThese make control variables only make sense when running tests. Please see Testing OpenJDK for details.
+TESTTEST_JOBSJTREGGTESTThese advanced make control variables can be potentially unsafe. See Hints and Suggestions for Advanced Users and Understanding the Build System for details.
+SPECCONF_CHECKCOMPARE_BUILDJDK_FILTERQ: When do I have to re-run configure?
-A: Normally you will run configure only once for creating a configuration. You need to re-run configuration only if you want to change any configuration options, or if you pull down changes to the configure script.
Q: I have added a new source file. Do I need to modify the makefiles?
-A: Normally, no. If you want to create e.g. a new native library, you will need to modify the makefiles. But for normal file additions or removals, no changes are needed. There are certan exceptions for some native libraries where the source files are spread over many directories which also contain sources for other libraries. In these cases it was simply easier to create include lists rather than excludes.
Q: When I run configure --help, I see many strange options, like --dvidir. What is this?
-A: Configure provides a slew of options by default, to all projects that use autoconf. Most of them are not used in OpenJDK, so you can safely ignore them. To list only OpenJDK specific features, use configure --help=short instead.
Q: configure provides OpenJDK-specific features such as --with-builddeps-server that are not described in this document. What about those?
-A: Try them out if you like! But be aware that most of these are experimental features. Many of them don't do anything at all at the moment; the option is just a placeholder. Others depend on pieces of code or infrastructure that is currently not ready for prime time.
Q: How will you make sure you don't break anything?
-A: We have a script that compares the result of the new build system with the result of the old. For most part, we aim for (and achieve) byte-by-byte identical output. There are however technical issues with e.g. native binaries, which might differ in a byte-by-byte comparison, even when building twice with the old build system. For these, we compare relevant aspects (e.g. the symbol table and file size). Note that we still don't have 100% equivalence, but we're close.
Q: I noticed this thing X in the build that looks very broken by design. Why don't you fix it?
-A: Our goal is to produce a build output that is as close as technically possible to the old build output. If things were weird in the old build, they will be weird in the new build. Often, things were weird before due to obscurity, but in the new build system the weird stuff comes up to the surface. The plan is to attack these things at a later stage, after the new build system is established.
Q: The code in the new build system is not that well-structured. Will you fix this?
-A: Yes! The new build system has grown bit by bit as we converted the old system. When all of the old build system is converted, we can take a step back and clean up the structure of the new build system. Some of this we plan to do before replacing the old build system and some will need to wait until after.
Q: Is anything able to use the results of the new build's default make target?
-A: Yes, this is the minimal (or roughly minimal) set of compiled output needed for a developer to actually execute the newly built JDK. The idea is that in an incremental development fashion, when doing a normal make, you should only spend time recompiling what's changed (making it purely incremental) and only do the work that's needed to actually run and test your code. The packaging stuff that is part of the images target is not needed for a normal developer who wants to test his new code. Even if it's quite fast, it's still unnecessary. We're targeting sub-second incremental rebuilds! ;-) (Or, well, at least single-digit seconds...)
Q: I usually set a specific environment variable when building, but I can't find the equivalent in the new build. What should I do?
-A: It might very well be that we have neglected to add support for an option that was actually used from outside the build system. Email us and we will add support for it!
Most of the OpenJDK tests are using the JTReg test framework. Make sure that your configuration knows where to find your installation of JTReg. If this is not picked up automatically, use the --with-jtreg=<path to jtreg home> option to point to the JTReg framework. Note that this option should point to the JTReg home, i.e. the top directory, containing lib/jtreg.jar etc.
To execute the most basic tests (tier 1), use:
+make run-test-tier1For more details on how to run tests, please see the Testing OpenJDK document.
+Cross-compiling means using one platform (the build platform) to generate output that can ran on another platform (the target platform).
+The typical reason for cross-compiling is that the build is performed on a more powerful desktop computer, but the resulting binaries will be able to run on a different, typically low-performing system. Most of the complications that arise when building for embedded is due to this separation of build and target systems.
+This requires a more complex setup and build procedure. This section assumes you are familiar with cross-compiling in general, and will only deal with the particularities of cross-compiling OpenJDK. If you are new to cross-compiling, please see the external links at Wikipedia for a good start on reading materials.
+Cross-compiling OpenJDK requires you to be able to build both for the build platform and for the target platform. The reason for the former is that we need to build and execute tools during the build process, both native tools and Java tools.
+If all you want to do is to compile a 32-bit version, for the same OS, on a 64-bit machine, consider using --with-target-bits=32 instead of doing a full-blown cross-compilation. (While this surely is possible, it's a lot more work and will take much longer to build.)
When cross-compiling, make sure you use a boot JDK that runs on the build system, and not on the target system.
+To be able to build, we need a "Build JDK", which is a JDK built from the current sources (that is, the same as the end result of the entire build process), but able to run on the build system, and not the target system. (In contrast, the Boot JDK should be from an older release, e.g. JDK 8 when building JDK 9.)
+The build process will create a minimal Build JDK for you, as part of building. To speed up the build, you can use --with-build-jdk to configure to point to a pre-built Build JDK. Please note that the build result is unpredictable, and can possibly break in subtle ways, if the Build JDK does not exactly match the current sources.
You must specify the target platform when cross-compiling. Doing so will also automatically turn the build into a cross-compiling mode. The simplest way to do this is to use the --openjdk-target argument, e.g. --openjdk-target=arm-linux-gnueabihf. or --openjdk-target=aarch64-oe-linux. This will automatically set the --build, --host and --target options for autoconf, which can otherwise be confusing. (In autoconf terminology, the "target" is known as "host", and "target" is used for building a Canadian cross-compiler.)
You will need two copies of your toolchain, one which generates output that can run on the target system (the normal, or target, toolchain), and one that generates output that can run on the build system (the build toolchain). Note that cross-compiling is only supported for gcc at the time being. The gcc standard is to prefix cross-compiling toolchains with the target denominator. If you follow this standard, configure is likely to pick up the toolchain correctly.
The build toolchain will be autodetected just the same way the normal build/target toolchain will be autodetected when not cross-compiling. If this is not what you want, or if the autodetection fails, you can specify a devkit containing the build toolchain using --with-build-devkit to configure, or by giving BUILD_CC and BUILD_CXX arguments.
It is often helpful to locate the cross-compilation tools, headers and libraries in a separate directory, outside the normal path, and point out that directory to configure. Do this by setting the sysroot (--with-sysroot) and appending the directory when searching for cross-compilations tools (--with-toolchain-path). As a compact form, you can also use --with-devkit to point to a single directory, if it is correctly setup. (See basics.m4 for details.)
If you are unsure what toolchain and versions to use, these have been proved working at the time of writing:
+ +You will need copies of external native libraries for the target system, present on the build machine while building.
+Take care not to replace the build system's version of these libraries by mistake, since that can render the build machine unusable.
+Make sure that the libraries you point to (ALSA, X11, etc) are for the target, not the build, platform.
+You will need alsa libraries suitable for your target system. For most cases, using Debian's pre-built libraries work fine.
+Note that alsa is needed even if you only want to build a headless JDK.
+Go to Debian Package Search and search for the libasound2 and libasound2-dev packages for your target system. Download them to /tmp.
Install the libraries into the cross-compilation toolchain. For instance:
+cd /tools/gcc-linaro-arm-linux-gnueabihf-raspbian-2012.09-20120921_linux/arm-linux-gnueabihf/libc
+dpkg-deb -x /tmp/libasound2_1.0.25-4_armhf.deb .
+dpkg-deb -x /tmp/libasound2-dev_1.0.25-4_armhf.deb .If alsa is not properly detected by configure, you can point it out by --with-alsa.
You will need X11 libraries suitable for your target system. For most cases, using Debian's pre-built libraries work fine.
+Note that X11 is needed even if you only want to build a headless JDK.
+Install the libraries into the cross-compilation toolchain. For instance:
+cd /tools/gcc-linaro-arm-linux-gnueabihf-raspbian-2012.09-20120921_linux/arm-linux-gnueabihf/libc/usr
+mkdir X11R6
+cd X11R6
+for deb in /tmp/target-x11/*.deb ; do dpkg-deb -x $deb . ; done
+mv usr/* .
+cd lib
+cp arm-linux-gnueabihf/* .You can ignore the following messages. These libraries are not needed to successfully complete a full JDK build.
+cp: cannot stat `arm-linux-gnueabihf/libICE.so': No such file or directory
+cp: cannot stat `arm-linux-gnueabihf/libSM.so': No such file or directory
+cp: cannot stat `arm-linux-gnueabihf/libXt.so': No such file or directoryIf the X11 libraries are not properly detected by configure, you can point them out by --with-x.
A common cross-compilation target is the ARM CPU. When building for ARM, it is useful to set the ABI profile. A number of pre-defined ABI profiles are available using --with-abi-profile: arm-vfp-sflt, arm-vfp-hflt, arm-sflt, armv5-vfp-sflt, armv6-vfp-hflt. Note that soft-float ABIs are no longer properly supported on OpenJDK.
OpenJDK contains two different ports for the aarch64 platform, one is the original aarch64 port from the AArch64 Port Project and one is a 64-bit version of the Oracle contributed ARM port. When targeting aarch64, by the default the original aarch64 port is used. To select the Oracle ARM 64 port, use --with-cpu-port=arm64. Also set the corresponding value (aarch64 or arm64) to --with-abi-profile, to ensure a consistent build.
The build will end up in a directory named like build/linux-arm-normal-server-release.
Inside this build output directory, the images/jdk and images/jre will contain the newly built JDK and JRE, respectively, for your target system.
Copy these folders to your target system. Then you can run e.g. images/jdk/bin/java -version.
Building OpenJDK requires a lot of horsepower. Some of the build tools can be adjusted to utilize more or less of resources such as parallel threads and memory. The configure script analyzes your system and selects reasonable values for such options based on your hardware. If you encounter resource problems, such as out of memory conditions, you can modify the detected values with:
--with-num-cores -- number of cores in the build system, e.g. --with-num-cores=8--with-memory-size -- memory (in MB) available in the build system, e.g. --with-memory-size=1024It might also be necessary to specify the JVM arguments passed to the Bootstrap JDK, using e.g. --with-boot-jdk-jvmargs="-Xmx8G -enableassertions". Doing this will override the default JVM arguments passed to the Bootstrap JDK.
One of the top goals of the new build system is to improve the build performance and decrease the time needed to build. This will soon also apply to the java compilation when the Smart Javac wrapper is fully supported.
-At the end of a successful execution of configure, you will get a performance summary, indicating how well the build will perform. Here you will also get performance hints. If you want to build fast, pay attention to those!
The OpenJDK build supports building with ccache when using gcc or clang. Using ccache can radically speed up compilation of native code if you often rebuild the same sources. Your milage may vary however so we recommend evaluating it for yourself. To enable it, make sure it's on the path and configure with --enable-ccache.
If you are using network shares, e.g. via NFS, for your source code, make sure the build directory is situated on local disk. The performance penalty is extremely high for building on a network share, close to unusable.
-The old build builds multiple JVMs on 32-bit systems (client and server; and on Windows kernel as well). In the new build we have changed this default to only build server when it's available. This improves build times for those not interested in multiple JVMs. To mimic the old behavior on platforms that support it, use --with-jvm-variants=client,server.
By default, configure will analyze your machine and run the make process in parallel with as many threads as you have cores. This behavior can be overridden, either "permanently" (on a configure basis) using --with-num-cores=N or for a single build only (on a make basis), using make JOBS=N.
If you want to make a slower build just this time, to save some CPU power for other processes, you can run e.g. make JOBS=2. This will force the makefiles to only run 2 parallel processes, or even make JOBS=1 which will disable parallelism.
If you want to have it the other way round, namely having slow builds default and override with fast if you're impatient, you should call configure with --with-num-cores=2, making 2 the default. If you want to run with more cores, run make JOBS=8
If the build fails (and it's not due to a compilation error in a source file you've changed), the first thing you should do is to re-run the build with more verbosity. Do this by adding LOG=debug to your make command line.
The build log (with both stdout and stderr intermingled, basically the same as you see on your console) can be found as build.log in your build directory.
You can ask for help on build problems with the new build system on either the build-dev or the build-infra-dev mailing lists. Please include the relevant parts of the build log.
-A build can fail for any number of reasons. Most failures are a result of trying to build in an environment in which all the pre-build requirements have not been met. The first step in troubleshooting a build failure is to recheck that you have satisfied all the pre-build requirements for your platform. Scanning the configure log is a good first step, making sure that what it found makes sense for your system. Look for strange error messages or any difficulties that configure had in finding things.
Some of the more common problems with builds are briefly described below, with suggestions for remedies.
-Corrupted Bundles on Windows:
-Some virus scanning software has been known to corrupt the downloading of zip bundles. It may be necessary to disable the 'on access' or 'real time' virus scanning features to prevent this corruption. This type of 'real time' virus scanning can also slow down the build process significantly. Temporarily disabling the feature, or excluding the build output directory may be necessary to get correct and faster builds.
Slow Builds:
-If your build machine seems to be overloaded from too many simultaneous C++ compiles, try setting the JOBS=1 on the make command line. Then try increasing the count slowly to an acceptable level for your system. Also:
Creating the javadocs can be very slow, if you are running javadoc, consider skipping that step.
-Faster CPUs, more RAM, and a faster DISK usually helps. The VM build tends to be CPU intensive (many C++ compiles), and the rest of the JDK will often be disk intensive.
-Faster compiles are possible using a tool called ccache.
---Warning message:
-File 'xxx' has modification time in the future.
-Warning message:Clock skew detected. Your build may be incomplete.
These warnings can occur when the clock on the build machine is out of sync with the timestamps on the source files. Other errors, apparently unrelated but in fact caused by the clock skew, can occur along with the clock skew warnings. These secondary errors may tend to obscure the fact that the true root cause of the problem is an out-of-sync clock.
-If you see these warnings, reset the clock on the build machine, run "gmake clobber" or delete the directory containing the build output, and restart the build from the beginning.
Trouble writing out table to disk---
make JOBS=1
to reduce the load on the system.
-Error Message: libstdc++ not found:
-This is caused by a missing libstdc++.a library. This is installed as part of a specific package (e.g. libstdc++.so.devel.386). By default some 64-bit Linux versions (e.g. Fedora) only install the 64-bit version of the libstdc++ package. Various parts of the JDK build require a static link of the C++ runtime libraries to allow for maximum portability of the built images.
Linux Error Message: cannot restore segment prot after reloc
-This is probably an issue with SELinux (See SELinux on Wikipedia). Parts of the VM is built without the -fPIC for performance reasons.
To completely disable SELinux:
-$ su root# system-config-securitylevelIn the window that appears, select the SELinux tabDisable SELinuxAlternatively, instead of completely disabling it you could disable just this one check.
-*** fatal error - couldn't allocate heap, ...rm fails with "Directory not empty"unzip fails with "cannot create ... Permission denied"unzip fails with "cannot create ... Error 50"The CYGWIN software can conflict with other non-CYGWIN software. See the CYGWIN FAQ section on BLODA (applications that interfere with CYGWIN).
-spawn failedThe Makefiles in the OpenJDK are only valid when used with the GNU version of the utility command make (usually called gmake on Solaris). A few notes about using GNU make:
PATH./usr/bin/make on Solaris. If your Solaris system has the software from the Solaris Developer Companion CD installed, you should try and use /usr/bin/gmake or /usr/gnu/bin/make.--with-num-cores -- number of cores in the build system, e.g. --with-num-cores=8.
--with-memory-size -- memory (in MB) available in the build system, e.g. --with-memory-size=1024
Information on GNU make, and access to ftp download sites, are available on the GNU make web site. The latest source to GNU make is available at ftp.gnu.org/pub/gnu/make/.
-First step is to get the GNU make 3.81 or newer source from ftp.gnu.org/pub/gnu/make/. Building is a little different depending on the OS but is basically done with:
- bash ./configure
- makeThis file often describes specific requirements for what we call the "minimum build environments" (MBE) for this specific release of the JDK. What is listed below is what the Oracle Release Engineering Team will use to build the Oracle JDK product. Building with the MBE will hopefully generate the most compatible bits that install on, and run correctly on, the most variations of the same base OS and hardware architecture. In some cases, these represent what is often called the least common denominator, but each Operating System has different aspects to it.
-In all cases, the Bootstrap JDK version minimum is critical, we cannot guarantee builds will work with older Bootstrap JDK's. Also in all cases, more RAM and more processors is better, the minimums listed below are simply recommendations.
-With Solaris and Mac OS X, the version listed below is the oldest release we can guarantee builds and works, and the specific version of the compilers used could be critical.
-With Windows the critical aspect is the Visual Studio compiler used, which due to it's runtime, generally dictates what Windows systems can do the builds and where the resulting bits can be used.
-NOTE: We expect a change here off these older Windows OS releases and to a 'less older' one, probably Windows 2008R2 X64.
-With Linux, it was just a matter of picking a stable distribution that is a good representative for Linux in general.
-It is understood that most developers will NOT be using these specific versions, and in fact creating these specific versions may be difficult due to the age of some of this software. It is expected that developers are more often using the more recent releases and distributions of these operating systems.
-Compilation problems with newer or different C/C++ compilers is a common problem. Similarly, compilation problems related to changes to the /usr/include or system header files is also a common problem with older, newer, or unreleased OS versions. Please report these types of problems as bugs so that they can be dealt with accordingly.
Bootstrap JDK: JDK 8
-| Base OS and Architecture | -OS | -C/C++ Compiler | -Processors | -RAM Minimum | -DISK Needs | -
|---|---|---|---|---|---|
| Linux X86 (32-bit) and X64 (64-bit) | -Oracle Enterprise Linux 6.4 | -gcc 4.9.2 | -2 or more | -1 GB | -6 GB | -
| Solaris SPARCV9 (64-bit) | -Solaris 11 Update 1 | -Studio 12 Update 4 + patches | -4 or more | -4 GB | -8 GB | -
| Solaris X64 (64-bit) | -Solaris 11 Update 1 | -Studio 12 Update 4 + patches | -4 or more | -4 GB | -8 GB | -
| Windows X86 (32-bit) | -Windows Server 2012 R2 x64 | -Microsoft Visual Studio C++ 2013 Professional Edition | -2 or more | -2 GB | -6 GB | -
| Windows X64 (64-bit) | -Windows Server 2012 R2 x64 | -Microsoft Visual Studio C++ 2013 Professional Edition | -2 or more | -2 GB | -6 GB | -
| Mac OS X X64 (64-bit) | -Mac OS X 10.9 "Mavericks" | -Xcode 6.3 or newer | -2 or more | -4 GB | -6 GB | -
We won't be listing all the possible environments, but we will try to provide what information we have available to us.
-NOTE: The community can help out by updating this part of the document.
-After installing the latest Fedora you need to install several build dependencies. The simplest way to do it is to execute the following commands as user root:
yum-builddep java-1.7.0-openjdk
- yum install gcc gcc-c++In addition, it's necessary to set a few environment variables for the build:
- export LANG=C
- export PATH="/usr/lib/jvm/java-openjdk/bin:${PATH}"After installing CentOS 5.5 you need to make sure you have the following Development bundles installed:
+You can also specify directly the number of build jobs to use with --with-jobs=N to configure, or JOBS=N to make. Do not use the -j flag to make. In most cases it will be ignored by the makefiles, but it can cause problems for some make targets.
It might also be necessary to specify the JVM arguments passed to the Boot JDK, using e.g. --with-boot-jdk-jvmargs="-Xmx8G". Doing so will override the default JVM arguments passed to the Boot JDK.
At the end of a successful execution of configure, you will get a performance summary, indicating how well the build will perform. Here you will also get performance hints. If you want to build fast, pay attention to those!
If you want to tweak build performance, run with make LOG=info to get a build time summary at the end of the build process.
If you are using network shares, e.g. via NFS, for your source code, make sure the build directory is situated on local disk (e.g. by ln -s /localdisk/jdk-build $JDK-SHARE/build). The performance penalty is extremely high for building on a network share; close to unusable.
Also, make sure that your build tools (including Boot JDK and toolchain) is located on a local disk and not a network share.
+As has been stressed elsewhere, do use SSD for source code and build directory, as well as (if possible) the build tools.
+The use of virus checking software, especially on Windows, can significantly slow down building of OpenJDK. If possible, turn off such software, or exclude the directory containing the OpenJDK source code from on-the-fly checking.
+The OpenJDK build supports building with ccache when using gcc or clang. Using ccache can radically speed up compilation of native code if you often rebuild the same sources. Your milage may vary however, so we recommend evaluating it for yourself. To enable it, make sure it's on the path and configure with --enable-ccache.
By default, the Hotspot build uses preccompiled headers (PCH) on the toolchains were it is properly supported (clang, gcc, and Visual Studio). Normally, this speeds up the build process, but in some circumstances, it can actually slow things down.
+You can experiment by disabling precompiled headers using --disable-precompiled-headers.
icecc/icecream is a simple way to setup a distributed compiler network. If you have multiple machines available for building OpenJDK, you can drastically cut individual build times by utilizing it.
+To use, setup an icecc network, and install icecc on the build machine. Then run configure using --enable-icecc.
To speed up Java compilation, especially incremental compilations, you can try the experimental sjavac compiler by using --enable-sjavac.
Selecting the proper target to build can have dramatic impact on build time. For normal usage, jdk or the default target is just fine. You only need to build images for shipping, or if your tests require it.
See also Using Fine-Grained Make Targets on how to build an even smaller subset of the product.
+If your build fails, it can sometimes be difficult to pinpoint the problem or find a proper solution.
+When a build fails, it can be hard to pinpoint the actual cause of the error. In a typical build process, different parts of the product build in parallel, with the output interlaced.
+To help you, the build system will print a failure summary at the end. It looks like this:
+ERROR: Build failed for target 'hotspot' in configuration 'linux-x64' (exit code 2)
+
+=== Output from failing command(s) repeated here ===
+* For target hotspot_variant-server_libjvm_objs_psMemoryPool.o:
+/localhome/hg/jdk9-sandbox/hotspot/src/share/vm/services/psMemoryPool.cpp:1:1: error: 'failhere' does not name a type
+ ... (rest of output omitted)
+
+* All command lines available in /localhome/hg/jdk9-sandbox/build/linux-x64/make-support/failure-logs.
+=== End of repeated output ===
+
+=== Make failed targets repeated here ===
+lib/CompileJvm.gmk:207: recipe for target '/localhome/hg/jdk9-sandbox/build/linux-x64/hotspot/variant-server/libjvm/objs/psMemoryPool.o' failed
+make/Main.gmk:263: recipe for target 'hotspot-server-libs' failed
+=== End of repeated output ===
+
+Hint: Try searching the build log for the name of the first failed target.
+Hint: If caused by a warning, try configure --disable-warnings-as-errors.Let's break it down! First, the selected configuration, and the top-level target you entered on the command line that caused the failure is printed.
+Then, between the Output from failing command(s) repeated here and End of repeated output the first lines of output (stdout and stderr) from the actual failing command is repeated. In most cases, this is the error message that caused the build to fail. If multiple commands were failing (this can happen in a parallel build), output from all failed commands will be printed here.
The path to the failure-logs directory is printed. In this file you will find a <target>.log file that contains the output from this command in its entirety, and also a <target>.cmd, which contain the complete command line used for running this command. You can re-run the failing command by executing . <path to failure-logs>/<target>.cmd in your shell.
Another way to trace the failure is to follow the chain of make targets, from top-level targets to individual file targets. Between Make failed targets repeated here and End of repeated output the output from make showing this chain is repeated. The first failed recipe will typically contain the full path to the file in question that failed to compile. Following lines will show a trace of make targets why we ended up trying to compile that file.
Finally, some hints are given on how to locate the error in the complete log. In this example, we would try searching the log file for "psMemoryPool.o". Another way to quickly locate make errors in the log is to search for "] Error" or "***".
Note that the build failure summary will only help you if the issue was a compilation failure or similar. If the problem is more esoteric, or is due to errors in the build machinery, you will likely get empty output logs, and No indication of failed target found instead of the make target chain.
The output (stdout and stderr) from the latest build is always stored in $BUILD/build.log. The previous build log is stored as build.log.old. This means that it is not necessary to redirect the build output yourself if you want to process it.
You can increase the verbosity of the log file, by the LOG control variable to make. If you want to see the command lines used in compilations, use LOG=cmdlines. To increase the general verbosity, use LOG=info, LOG=debug or LOG=trace. Both of these can be combined with cmdlines, e.g. LOG=info,cmdlines. The debug log level will show most shell commands executed by make, and trace will show all. Beware that both these log levels will produce a massive build log!
Most of the time, the build will fail due to incorrect changes in the source code.
+Sometimes the build can fail with no apparent changes that have caused the failure. If this is the first time you are building OpenJDK on this particular computer, and the build fails, the problem is likely with your build environment. But even if you have previously built OpenJDK with success, and it now fails, your build environment might have changed (perhaps due to OS upgrades or similar). But most likely, such failures are due to problems with the incremental rebuild.
+Make sure your configuration is correct. Re-run configure, and look for any warnings. Warnings that appear in the middle of the configure output is also repeated at the end, after the summary. The entire log is stored in $BUILD/configure.log.
Verify that the summary at the end looks correct. Are you indeed using the Boot JDK and native toolchain that you expect?
+By default, OpenJDK has a strict approach where warnings from the compiler is considered errors which fail the build. For very new or very old compiler versions, this can trigger new classes of warnings, which thus fails the build. Run configure with --disable-warnings-as-errors to turn of this behavior. (The warnings will still show, but not make the build fail.)
Incremental rebuilds mean that when you modify part of the product, only the affected parts get rebuilt. While this works great in most cases, and significantly speed up the development process, from time to time complex interdependencies will result in an incorrect build result. This is the most common cause for unexpected build problems, together with inconsistencies between the different Mercurial repositories in the forest.
+Here are a suggested list of things to try if you are having unexpected build problems. Each step requires more time than the one before, so try them in order. Most issues will be solved at step 1 or 2.
+Make sure your forest is up-to-date
+Run bash get_source.sh to make sure you have the latest version of all repositories.
Clean build results
+The simplest way to fix incremental rebuild issues is to run make clean. This will remove all build results, but not the configuration or any build system support artifacts. In most cases, this will solve build errors resulting from incremental build mismatches.
Completely clean the build directory.
+If this does not work, the next step is to run make dist-clean, or removing the build output directory ($BUILD). This will clean all generated output, including your configuration. You will need to re-run configure after this step. A good idea is to run make print-configuration before running make dist-clean, as this will print your current configure command line. Here's a way to do this:
make print-configuration > current-configuration
+make dist-clean
+bash configure $(cat current-configuration)
+makeRe-clone the Mercurial forest
+Sometimes the Mercurial repositories themselves gets in a state that causes the product to be un-buildable. In such a case, the simplest solution is often the "sledgehammer approach": delete the entire forest, and re-clone it. If you have local changes, save them first to a different location using hg export.
If you get an error message like this:
+File 'xxx' has modification time in the future.
+Clock skew detected. Your build may be incomplete.then the clock on your build machine is out of sync with the timestamps on the source files. Other errors, apparently unrelated but in fact caused by the clock skew, can occur along with the clock skew warnings. These secondary errors may tend to obscure the fact that the true root cause of the problem is an out-of-sync clock.
+If you see these warnings, reset the clock on the build machine, run make clean and restart the build.
On Solaris, you might get an error message like this:
+Trouble writing out table to diskTo solve this, increase the amount of swap space on your build machine.
+On Windows, you might get error messages like this:
+fatal error - couldn't allocate heap
+cannot create ... Permission denied
+spawn failedThis can be a sign of a Cygwin problem. See the information about solving problems in the Cygwin section. Rebooting the computer might help temporarily.
+If none of the suggestions in this document helps you, or if you find what you believe is a bug in the build system, please contact the Build Group by sending a mail to build-dev@openjdk.java.net. Please include the relevant parts of the configure and/or build log.
+If you need general help or advice about developing for OpenJDK, you can also contact the Adoption Group. See the section on Contributing to OpenJDK for more information.
+To help you prepare a proper push path for a Mercurial repository, there exists a useful tool known as defpath. It will help you setup a proper push path for pushing changes to OpenJDK.
+Install the extension by cloning http://hg.openjdk.java.net/code-tools/defpath and updating your .hgrc file. Here's one way to do this:
cd ~
+mkdir hg-ext
+cd hg-ext
+hg clone http://hg.openjdk.java.net/code-tools/defpath
+cat << EOT >> ~/.hgrc
+[extensions]
+defpath=~/hg-ext/defpath/defpath.py
+EOTYou can now setup a proper push path using:
+hg defpath -d -u <your OpenJDK username>If you also have the trees extension installed in Mercurial, you will automatically get a tdefpath command, which is even more useful. By running hg tdefpath -du <username> in the top repository of your forest, all repos will get setup automatically. This is the recommended usage.
The configure and make commands tries to play nice with bash command-line completion (using <tab> or <tab><tab>). To use this functionality, make sure you enable completion in your ~/.bashrc (see instructions for bash in your operating system).
Make completion will work out of the box, and will complete valid make targets. For instance, typing make jdk-i<tab> will complete to make jdk-image.
The configure script can get completion for options, but for this to work you need to help bash on the way. The standard way of running the script, bash configure, will not be understood by bash completion. You need configure to be the command to run. One way to achieve this is to add a simple helper script to your path:
cat << EOT > /tmp/configure
+#!/bin/bash
+if [ \$(pwd) = \$(cd \$(dirname \$0); pwd) ] ; then
+ echo >&2 "Abort: Trying to call configure helper recursively"
+ exit 1
+fi
+
+bash \$PWD/configure "\$@"
+EOT
+chmod +x /tmp/configure
+sudo mv /tmp/configure /usr/local/binNow configure --en<tab>-dt<tab> will result in configure --enable-dtrace.
You can have multiple configurations for a single source forest. When you create a new configuration, run configure --with-conf-name=<name> to create a configuration with the name <name>. Alternatively, you can create a directory under build and run configure from there, e.g. mkdir build/<name> && cd build/<name> && bash ../../configure.
Then you can build that configuration using make CONF_NAME=<name> or make CONF=<pattern>, where <pattern> is a substring matching one or several configurations, e.g. CONF=debug. The special empty pattern (CONF=) will match all available configuration, so make CONF= hotspot will build the hotspot target for all configurations. Alternatively, you can execute make in the configuration directory, e.g. cd build/<name> && make.
If you update the forest and part of the configure script has changed, the build system will force you to re-run configure.
Most of the time, you will be fine by running configure again with the same arguments as the last time, which can easily be performed by make reconfigure. To simplify this, you can use the CONF_CHECK make control variable, either as make CONF_CHECK=auto, or by setting an environment variable. For instance, if you add export CONF_CHECK=auto to your .bashrc file, make will always run reconfigure automatically whenever the configure script has changed.
You can also use CONF_CHECK=ignore to skip the check for a needed configure update. This might speed up the build, but comes at the risk of an incorrect build result. This is only recommended if you know what you're doing.
From time to time, you will also need to modify the command line to configure due to changes. Use make print-configure to show the command line used for your current configuration.
The default behavior for make is to create consistent and correct output, at the expense of build speed, if necessary.
+If you are prepared to take some risk of an incorrect build, and know enough of the system to understand how things build and interact, you can speed up the build process considerably by instructing make to only build a portion of the product.
+The safe way to use fine-grained make targets is to use the module specific make targets. All source code in JDK 9 is organized so it belongs to a module, e.g. java.base or jdk.jdwp.agent. You can build only a specific module, by giving it as make target: make jdk.jdwp.agent. If the specified module depends on other modules (e.g. java.base), those modules will be built first.
You can also specify a set of modules, just as you can always specify a set of make targets: make jdk.crypto.cryptoki jdk.crypto.ec jdk.crypto.mscapi jdk.crypto.ucrypto
The build process for each module is divided into separate phases. Not all modules need all phases. Which are needed depends on what kind of source code and other artifact the module consists of. The phases are:
gensrc (Generate source code to compile)gendata (Generate non-source code artifacts)copy (Copy resource artifacts)java (Compile Java code)launchers (Compile native executables)libs (Compile native libraries)rmic (Run the rmic tool)Plus the following packages:
+You can build only a single phase for a module by using the notation $MODULE-$PHASE. For instance, to build the gensrc phase for java.base, use make java.base-gensrc.
Note that some phases may depend on others, e.g. java depends on gensrc (if present). Make will build all needed prerequisites before building the requested phase.
When using an iterative development style with frequent quick rebuilds, the dependency check made by make can take up a significant portion of the time spent on the rebuild. In such cases, it can be useful to bypass the dependency check in make.
+++Note that if used incorrectly, this can lead to a broken build!
+
To achieve this, append -only to the build target. For instance, make jdk.jdwp.agent-java-only will only build the java phase of the jdk.jdwp.agent module. If the required dependencies are not present, the build can fail. On the other hand, the execution time measures in milliseconds.
A useful pattern is to build the first time normally (e.g. make jdk.jdwp.agent) and then on subsequent builds, use the -only make target.
If you are modifying files in java.base, which is the by far largest module in OpenJDK, then you need to rebuild all those files whenever a single file has changed. (This inefficiency will hopefully be addressed in JDK 10.)
As a hack, you can use the make control variable JDK_FILTER to specify a pattern that will be used to limit the set of files being recompiled. For instance, make java.base JDK_FILTER=javax/crypto (or, to combine methods, make java.base-java-only JDK_FILTER=javax/crypto) will limit the compilation to files in the javax.crypto package.
To become an efficient OpenJDK developer, it is recommended that you invest in learning Mercurial properly. Here are some links that can get you started:
The freetype 2.3 packages don't seem to be available, but the freetype 2.3 sources can be downloaded, built, and installed easily enough from the freetype site. Build and install with something like:
- bash ./configure
- make
- sudo -u root make installMercurial packages could not be found easily, but a Google search should find ones, and they usually include Python if it's needed.
-After installing Debian 5 you need to install several build dependencies. The simplest way to install the build dependencies is to execute the following commands as user root:
aptitude build-dep openjdk-7
- aptitude install openjdk-7-jdk libmotif-devIn addition, it's necessary to set a few environment variables for the build:
- export LANG=C
- export PATH="/usr/lib/jvm/java-7-openjdk/bin:${PATH}"After installing Ubuntu 12.04 you need to install several build dependencies. The simplest way to do it is to execute the following commands:
- sudo aptitude build-dep openjdk-7
- sudo aptitude install openjdk-7-jdkIn addition, it's necessary to set a few environment variables for the build:
- export LANG=C
- export PATH="/usr/lib/jvm/java-7-openjdk/bin:${PATH}"After installing OpenSUSE 11.1 you need to install several build dependencies. The simplest way to install the build dependencies is to execute the following commands:
- sudo zypper source-install -d java-1_7_0-openjdk
- sudo zypper install makeIn addition, it is necessary to set a few environment variables for the build:
- export LANG=C
- export PATH="/usr/lib/jvm/java-1.7.0-openjdk/bin:$[PATH}"Finally, you need to unset the JAVA_HOME environment variable:
export -n JAVA_HOME`After installing Mandriva Linux One 2009 Spring you need to install several build dependencies. The simplest way to install the build dependencies is to execute the following commands as user root:
urpmi java-1.7.0-openjdk-devel make gcc gcc-c++ freetype-devel zip unzip
- libcups2-devel libxrender1-devel libalsa2-devel libstc++-static-devel
- libxtst6-devel libxi-develIn addition, it is necessary to set a few environment variables for the build:
- export LANG=C
- export PATH="/usr/lib/jvm/java-1.7.0-openjdk/bin:${PATH}"After installing OpenSolaris 2009.06 you need to install several build dependencies. The simplest way to install the build dependencies is to execute the following commands:
- pfexec pkg install SUNWgmake SUNWj7dev sunstudioexpress SUNWcups SUNWzip
- SUNWunzip SUNWxwhl SUNWxorg-headers SUNWaudh SUNWfreetype2In addition, it is necessary to set a few environment variables for the build:
- export LANG=C
- export PATH="/opt/SunStudioExpress/bin:${PATH}"End of the OpenJDK build README document.
-Please come again!
+This section will give you a more technical description on the details of the build system.
+The build system expects to find one or more configuration. These are technically defined by the spec.gmk in a subdirectory to the build subdirectory. The spec.gmk file is generated by configure, and contains in principle the configuration (directly or by files included by spec.gmk).
You can, in fact, select a configuration to build by pointing to the spec.gmk file with the SPEC make control variable, e.g. make SPEC=$BUILD/spec.gmk. While this is not the recommended way to call make as a user, it is what is used under the hood by the build system.
The build output for a configuration will end up in build/<configuration name>, which we refer to as $BUILD in this document. The $BUILD directory contains the following important directories:
buildtools/
+configure-support/
+hotspot/
+images/
+jdk/
+make-support/
+support/
+test-results/
+test-support/This is what they are used for:
+images: This is the directory were the output of the *-image make targets end up. For instance, make jdk-image ends up in images/jdk.
jdk: This is the "exploded image". After make jdk, you will be able to launch the newly built JDK by running $BUILD/jdk/bin/java.
test-results: This directory contains the results from running tests.
support: This is an area for intermediate files needed during the build, e.g. generated source code, object files and class files. Some noteworthy directories in support is gensrc, which contains the generated source code, and the modules_* directories, which contains the files in a per-module hierarchy that will later be collapsed into the jdk directory of the exploded image.
buildtools: This is an area for tools compiled for the build platform that are used during the rest of the build.
hotspot: This is an area for intermediate files needed when building hotspot.
configure-support, make-support and test-support: These directories contain files that are needed by the build system for configure, make and for running tests.
Windows path typically look like C:\User\foo, while Unix paths look like /home/foo. Tools with roots from Unix often experience issues related to this mismatch when running on Windows.
In the OpenJDK build, we always use Unix paths internally, and only just before calling a tool that does not understand Unix paths do we convert them to Windows paths.
+This conversion is done by the fixpath tool, which is a small wrapper that modifies unix-style paths to Windows-style paths in command lines. Fixpath is compiled automatically by configure.
Native libraries and executables can have debug symbol (and other debug information) associated with them. How this works is very much platform dependent, but a common problem is that debug symbol information takes a lot of disk space, but is rarely needed by the end user.
+The OpenJDK supports different methods on how to handle debug symbols. The method used is selected by --with-native-debug-symbols, and available methods are none, internal, external, zipped.
none means that no debug symbols will be generated during the build.
internal means that debug symbols will be generated during the build, and they will be stored in the generated binary.
external means that debug symbols will be generated during the build, and after the compilation, they will be moved into a separate .debuginfo file. (This was previously known as FDS, Full Debug Symbols).
zipped is like external, but the .debuginfo file will also be zipped into a .diz file.
When building for distribution, zipped is a good solution. Binaries built with internal is suitable for use by developers, since they facilitate debugging, but should be stripped before distributed to end users.
The configure script is based on the autoconf framework, but in some details deviate from a normal autoconf configure script.
The configure script in the top level directory of OpenJDK is just a thin wrapper that calls common/autoconf/configure. This in turn provides functionality that is not easily expressed in the normal Autoconf framework, and then calls into the core of the configure script, which is the common/autoconf/generated-configure.sh file.
As the name implies, this file is generated by Autoconf. It is checked in after regeneration, to alleviate the common user to have to install Autoconf.
+The build system will detect if the Autoconf source files have changed, and will trigger a regeneration of common/autoconf/generated-configure.sh if needed. You can also manually request such an update by bash common/autoconf/autogen.sh.
If you make changes to the build system that requires a re-generation, note the following:
+You must use exactly version 2.69 of autoconf for your patch to be accepted. This is to avoid spurious changes in the generated file. Note that Ubuntu 16.04 ships a patched version of autoconf which claims to be 2.69, but is not.
You do not need to include the generated file in reviews.
If the generated file needs updating, the Oracle JDK closed counter-part will also need to be updated. It is very much appreciated if you ask for an Oracle engineer to sponsor your push so this can be made in tandem.
This section contains a few remarks about how to develop for the build system itself. It is not relevant if you are only making changes in the product source code.
+While technically using make, the make source files of the OpenJDK does not resemble most other Makefiles. Instead of listing specific targets and actions (perhaps using patterns), the basic modus operandi is to call a high-level function (or properly, macro) from the API in make/common. For instance, to compile all classes in the jdk.internal.foo package in the jdk.foo module, a call like this would be made:
$(eval $(call SetupJavaCompilation, BUILD_FOO_CLASSES, \
+ SETUP := GENERATE_OLDBYTECODE, \
+ SRC := $(JDK_TOPDIR)/src/jkd.foo/share/classes, \
+ INCLUDES := jdk/internal/foo, \
+ BIN := $(SUPPORT_OUTPUTDIR)/foo_classes, \
+))By encapsulating and expressing the high-level knowledge of what should be done, rather than how it should be done (as is normal in Makefiles), we can build a much more powerful and flexible build system.
+Correct dependency tracking is paramount. Sloppy dependency tracking will lead to improper parallelization, or worse, race conditions.
+To test for/debug race conditions, try running make JOBS=1 and make JOBS=100 and see if it makes any difference. (It shouldn't).
To compare the output of two different builds and see if, and how, they differ, run $BUILD1/compare.sh -o $BUILD2, where $BUILD1 and $BUILD2 are the two builds you want to compare.
To automatically build two consecutive versions and compare them, use COMPARE_BUILD. The value of COMPARE_BUILD is a set of variable=value assignments, like this:
make COMPARE_BUILD=CONF=--enable-new-hotspot-feature:MAKE=hotspotSee make/InitSupport.gmk for details on how to use COMPARE_BUILD.
To analyze build performance, run with LOG=trace and check $BUILD/build-trace-time.log. Use JOBS=1 to avoid parallelism.
Please check that you adhere to the Code Conventions for the Build System before submitting patches. Also see the section in Autoconf Details about the generated configure script.
+So, now you've build your OpenJDK, and made your first patch, and want to contribute it back to the OpenJDK community.
+First of all: Thank you! We gladly welcome your contribution to the OpenJDK. However, please bear in mind that OpenJDK is a massive project, and we must ask you to follow our rules and guidelines to be able to accept your contribution.
+The official place to start is the 'How to contribute' page. There is also an official (but somewhat outdated and skimpy on details) Developer's Guide.
+If this seems overwhelming to you, the Adoption Group is there to help you! A good place to start is their 'New Contributor' page, or start reading the comprehensive Getting Started Kit. The Adoption Group will also happily answer any questions you have about contributing. Contact them by mail or IRC.