Working on OpenJDK using NetBeans

    This note describes how to work on the OpenJDK from NetBeans. We've

    provided several NetBeans projects as starting points. Below we'll

    describe how to use them, as well as how to create your own.

Getting Started

    In addition to the source bundle for Open JDK, you'll need to download

    and install copies of the JDK and of NetBeans. And if you want to run

    tests on the JDK (you do want to run tests, right?), you'll need to

    install the jtreg test harness.

    In this note, when pathnames are not fully specified, they should be

    interpreted as being relative to the directory containing this README

    and the NetBeans projects themselves.

        The JDK build process is largely make-based, and is not

        exceptionally tolerant of pathnames with spaces in them (such as

        "Program Files". Please be sure to install everything in a

        directories whose paths don't have any spaces!

    Downloading the JDK

        You've probably done this a million times. Download and install it

        from http://www.oracle.com/technetwork/java/javase/overview/index.html

    Downloading the OpenJDK sources

        Since you're reading this, d you've already downloaded the OpenJDK

        source bundle.  Later in this document we'll refer to the location

        where you installed the Open JDK sources as *install-dir*.

    Downloading a pre-built, JDK 8

        This will be necessary to do builds of some of the projects.  In

        general, you want to download and install a pre-built JDK that

        corresponds to the OpenJDK sources you download.  Building the entire

        OpenJDK depends on a few parts of the pre-built JDK.  Get this from

        http://download.java.net/jdk8/binaries

        Note: For working on certain projects, like JMX and JConsole, you

              may find convenient to use a pre-built version of JDK 8 (or

              OpenJDK) rather than building your own. This will allow you

              to build only that part of the OpenJDK sources which correspond

              to that project.

    NetBeans 7.0 or later

        Older versions may also work but are unsupported.

    jtreg

        "jtreg" is the test harness for running OpenJDK's regression tests.

        Get it from http://openjdk.java.net/jtreg

    Ant

       NetBeans comes with ant, but if you use a separately-installed copy

       please make sure that it is at least version 1.8.1.

Configuring

    Building OpenJDK is hard and complex. No, strike that. While it's not

    exactly "easy", we've got it down to *relatively* small set of

    properties you need to set.

    The NetBeans projects provided here share a fair amount of common

    structure. They share properties values where it makes sense. Each

    project loads properties from these properties files, in this order

        ${basedir}/nbproject/private/build.properties

        $HOME/.openjdk/${ant.project.name}-build.properties

        $HOME/.openjdk/build.properties

        ${basedir}/build.properties

    (${basedir} refers to the directory containing a particular NetBeans

    project.) The first time a property defined determines value: it is

    *not* overridden if it is read from properties files read later. The net

    result is that by carefully choosing where to define a property, you can

    have it for a specific project, all uses of a specific project (useful

    if you work on multiple copies of the OpenJDK sources), all projects, or

    only projects in a specific sandbox.

    With that in mind, please set the following properties. Presuming you

    want the same values for all your work, set them in

    $HOME/.openjdk/build.properties.

    * bootstrap.jdk

        Set to the location where you installed JDK 7.

    * jtreg.home

        Set to the location where you installed jtreg.

    * make.options

        Some of the projects invoke "make", since they compile native code.

        The make.options property is for passing information about what you

        installed where to make.  Change the paths to fit your particular

        situation:

        make.options=\

            ALT_BOOTDIR=/home/me/bin/jdk1.7.0 \

            ALT_JDK_IMPORT_PATH=/home/me/bin/jdk1.8.0 \

            OPENJDK=true

        The trailing '\' are important, so that make gets the above as a

        single set of options.

        You might want to add additional additional options: see the README

        for the project you're using for more information.  And see

                 *install-dir*/jdk/make/README-builds.html

        to read much more about building the JDK.

  Windows-specific configuration

    First, please note that the entire JDK cannot currently be built on

    Windows platforms.  This will likely limit your ability to build

    make-based projects.  See

         *install-dir*/jdk/make/README-builds.html

    for full information on issues with building on the Windows platform.

    That said, there are two ways to work with the Windows-required settings

    for the Microsoft tools. Either:

    * Set environment variables values in Windows

        Doing so means accessing the System control panel in Windows, and

        setting the environment variables there.

        By doing so, you can launch NetBeans by double-clicking its icon,

        and the environment variable values will be available.

    * Set environment variable values in a shell

        Doing so means adding the settings to an init file (e.g. .bashrc,

        .cshrc, etc.) or a file that you source before running NetBeans. In

        this case, you'll have to launch NetBeans from the command line in a

        shell in which you've set the environment variables.

    In either case, the end result should be that the settings are available

    to the make-based build process when it runs from within NetBeans.

    The make-based builds presumes that you're using cygwin, and expects to

    find "make" in c:\cygwin\bin\make. If you've installed cygwin elsewhere,

    set "make" in a properties file.

  Configuring Project Properties

    A note of caution is in order: These are NetBeans *freeform* projects.

    If you use the NetBeans GUI to examine them, things are likely to not

    look "right". Please don't edit them there, please instead use a text

    editor.

  Locale Requirements

    To build the OpenJDK sources, be certain that you are using the "C"

    locale on Unix (R) platforms, or "English (United States)" locale on

    Windows.

Platforms and architectures, oh my!

    The Open JDK can be built for a variety of operating system platforms

    and hardware architectures. The resulting builds are always placed in a

    directory which contains the platform and architecture as part of the

    pathname, as in *platform*-*arch*. For example, if you build the jdk

    project on a Linux platform running on x86 hardware, the resulting build

    will be in:

    *install-dir*/jdk/build/linux-i586

    We've provided support for some platforms and architectures in

    common/architectures. Add another, if your needs require it.

Provided NetBeans projects

    This section describes the NetBeans projects that help you work on

    particular parts of the JDK. While they're largely similar in structure

    and should work the way you expect NetBeans projects to work: edit,

    build, test, etc. But there are some differences. They don't all support

    the same targets (e.g., there's nothing to run in jarzip project).

    Some projects are built by invoking make, since they involve compilation

    of native code or other activities that cannot be done by javac. We call

    these "make-based", and call all others "ant-based".

    They all are configured by way of a build.properties file, which

    specifies what subdirectories of the JDK sources they manipulate, what

    directories contain their tests, whether they use make or ant, etc.

    The very first time you open any one of these projects on set of Open

    JDK sources, NetBeans will scan the entire set of sources, not just

    those for the project you opened. This will take a few minutes, but will

    ensure that Go To Type, Go To Source, and so on work as expected. Later,

    when you open other projects on the same Open JDK sources, there will be

    at most a slight delay.

    There's a README accompanying each project. Most are text files, which

    you can Open in NetBeans, some are HTML files, in which case unless you

    enjoy reading raw HTML, you're better off choosing the *View* menu item

    from the context menu, which will display the README in your web

    browser.

    Finally, note that these projects were all created by different people,

    and are while some attempt has been made to make them look and behave

    the same, they are maintained separately and will vary somewhat.

    The projects currently provided are:

    jdk (directory "jdk")

        A convenient starting point for the other projects, and from which

        you can build the entire OpenJDK. Please note that depending on your

        hardware, this could take a *very* long time. The results of the

        build are in *install-dir*/jdk/build/*platform*-*arch*.

    world (directory "world")

        This project builds both the Hotspot VM and all of JavaSE. Please

        note that pretty much regardless of your hardware, this *will* take

        a long time, and use *lots* of disk space (more than 3GB). The

        results of the build are in

        *install-dir*/build/*platform*-*arch* and

        *install-dir*/build/*platform*-*arch*-fastdebug.

        Consult the project's README file for details.

    AWT & Java2d (directory "awt2d")

        For working on AWT and Java2d. Supports running the Font2DTest demo.

        This is a make-based project: In order to build this project, you

        should build the jdk project first, since AWT and Java2d include

        native code.

    JConsole (directory "jconsole")

        For working on JConsole. Creates ../dist/lib/jconsole.jar. Supports

        running and debugging JConsole.

        This ant-based project does *not* require that you build the jdk

        project first, provided that you use a pre-built version of JDK 7.

    Java (TM) Management Extensions (JMX(TM)) API (directory "jmx")

        For working on JMX source code. Creates ../dist/lib/jmx.jar.

        This ant-based project does *not* require that you build the jdk

        project first, provided that you use a pre-built version of JDK 7.

    Jar & Zip (directory "jarzip")

        For working on jar & zip. It builds the zip library (including

        native code), the jar library, and the jar tool. Creates an

        executable jar program in ../build/*platform*-*arch*/bin/jar.

        This is a make-based project: In order to build this project, you

        should build the jdk project first, since AWT and Java2d include

        native code.

    Swing (directory "swing")

        For working on Swing. Creates ../dist/lib/swing.jar. Supports

        running and debugging the SampleTree demo.

        This ant-based project does *not* require that you build the jdk

        project first, provided that you use a pre-built version of JDK 7.

    In addition, there are projects for building the compiler, javadoc,

    and related tools, in the OpenJDK langtools component.  These

    projects are separate from those described here, and have their

    own set of guidelines and conventions. For more details, see the

    README files in make/netbeans in the OpenJDK langtools component.

Running Tests

    We use the jtreg test harness, described more fully at

    http://openjdk.java.net/jtreg

    The OpenJDK tests are in the default Java package, are public classes,

    and have a "static void main(String[] args)" with which they are

    invoked. Some tests are actually shell scripts, which might compile

    code, etc. jtreg is quite flexible.

    To run tests for a project, use *Test Project* from NetBeans. From the

    command line, you can invoke "ant jtreg" on any individual project's

    build.xml file.

    In either NetBeans of on the command line, jtreg prints summary output

    about the pass/fail nature of each test. An HTML report of the entire

    test run is

    ../build/*platform*-*arch*/jtreg/*ant-project-name*/JTreport/report.html

    In that same JTreport directory are also individual HTML files

    summarizing the test environment, test passes and failures, etc.

    More detail on any individual test is under

    ../build/*platform*-*arch*/jtreg/*ant-project-name*/JTwork.

    For example, details about the awt/Modal/SupportedTest/SupportedTest

    test are under the JTwork directory at the same pathname as the test

    itself in a ".jtr" file. For example:

    ../build/*platform*-*arch*/jtreg/*ant-project-name*/JTwork/awt/Modal/SupportedTest/SupportedTest.jtr

    Sometimes you will see that running jtreg has resulted in a failure.

    This does not always mean that a test has an error in it. Jtreg

    distinguishes between these two cases. There are a number of tests that

    are "ignored", and not run, and these are reported as failures.

    You can run a single test by right clicking on it and choosing *Run

    File* from the context menu. Similarly, you can debug a single test by

    choosing *Debug File*.

Debugging

    Debugging is enabled by default in ant-based projects, as if

    "-g:lines,vars,source" were given. You can alter these settings via

    entries in one of the configuration properties files. For example:

     javac.debug=false

     javac.debuglevel=<debug level options>

    To debug a project or test, use NetBeans in the normal way, with *Debug

    Project* or *Debug File*. Note that not all projects provide a target

    that can be debugged, but tests can be debugged.

Creating Javadoc

    You can create Javadoc for any of the projects: just choose *Generate

    Javadoc for Project* from the NetBeans menu. Your default browser will

    open up, displaying the just-generated javadoc.

    Javadoc gets generated into a separate subdirectory for each project.

    For example, the Jar & Zip project's javadoc gets generated in

    ../build/*platform*-*arch*/jtreg/*ant-project-name*/javadoc/jarzip

Cleaning projects

    Each project can of course be cleaned. Make-based and ant-based projects

    differ a little in what exactly gets cleaned. In both cases, all jtreg

    results and javadoc are removed.

    In ant-based projects, project-specific files as determined by the

    project's build.properties file are removed from the classes and gensrc

    directories that are under ../build/*platform*-*arch*.

    In make-based projects, "make clean" is run in the same directories as

    "make all" is run when building the project.

    Please note that the jdk project is "special" with respect to

    cleaning: in this case, the entire ../build directory is removed.

    Similar for the world project.

Creating your own NetBeans project

    The project's we've provided are hopefully a useful starting point, but

    chances are that you want to work on something else. This section will

    describe how to select an existing project, and then adapt it to your

    needs.

  Considerations

    The first consideration is whether or not the code in which you're

    interested needs anything beyond javac and copying of resources to

    build. If so, then you'll need to create a make-based project. If not,

    an ant-based project is possible. See the project descriptions above to

    learn which are make-based, and which are ant-based.

    The second consideration is to consider the files that you'll need. Each

    project is defined by 3 files:

    * build.xml

        This is the ant build script. For a make-based project, they tend to

        have a target for "make clean" and another for "make all", each of

        which invokes "make-run" in the same set of directories. Take a look

        at jarzip/build.xml for an example.

        For an ant-based project, there might be nothing, with all the work

        done via the declaration of properties in the build.properties file.

        Take a look at jconsole/build.xml for an example, and notice how it

        overrides the -pre-compile and -post-compile targets that are

        defined in common/shared.xml (where they are defined to do nothing).

    * build.properties

        This file defines the directories (and possibly files) that are

        included in and excluded from. Basically, a file is considered to be

        in a project if it is mentioned in the includes list, or is

        contained under a directory mentioned in that list, *unless* it is

        explicitly excluded or is contained under a directory that is

        excluded. Take a look awt2d/build.properties for an example.

    * nbproject/project.xml

        This file defines a project for NetBeans for a "freeform" project.

        Each declares several entity references, which are used later in the

        project. For an example, see javadoc/nbproject/project.xml, which is

        an ant-based project. Compare that with

        jarzip/nbproject/project.xml, which is make-based. Not much

        difference! That's because while the jarzip project is make-based,

        it does not have any platform-specifc native code. Contrast that

        with awt2d/nbproject/project.xml, which does have native code;

        notice that it uses platform-specific entity references.

    In summary, we recommend exploring the given projects, and choosing one

    that most closely suits our needs.

  Example: A project for working on collections

    Let's create a project to work with on the collections classes. There's no native

    code here, so an ant-based project will do. Therefore, the jconsole

    project is a reasonable project to use as a starting point.

   Clone the existing project

    Make a directory for the collections project next to the existing projects:

        % mkdir -p collections/nbproject

    Copy files from the jconsole project:

        % cp jconsole/build.properties collections

        % cp jconsole/build.xml collections

        % cp jconsole/nbproject/project.xml collections/nbproject

   Change the set of files included in the project

    The collections sources are all under one directory, and we want to include

    them all. The same is true of the tests. So edit

    collections/build.properties so that it contains these lines:

        includes=\

            java/util/

        excludes=\

            java/util/Calendar.java,\

            java/util/jar/,\

            java/util/logging/,\

            java/util/prefs/,\

            java/util/regex/,\

            java/util/spi/,\

            java/util/zip/,\

            **/*-XLocales.java.template

        jtreg.tests=\

            java/util/**/*Collection/ \

            java/util/**/*Map/ \

            java/util/**/*Set/ \

            java/util/**/*List/

    Notice the trailing "/" in some of those pathnames: that tells NetBeans to

    treat the path as a directory and include (or exclude) everything beneath

    it in the hierarchy.  Note also how we include java/util, but then exclude

    several directories under that which are not related to collections.

    The build.xml for collections is about as simple as can be. First, change the

    name of the project:

        <project name="collections" default="build" basedir=".">

    Then remove the -pre-compile target from the build.xml.  Change the

    -post-compile target to create collections.jar without any manifest, and

    to only contain the collections-related classes.  The jar task now looks

    like this:

        <jar destfile="${dist.dir}/lib/collections.jar">

            <fileset dir="${classes.dir}">

                <include name="java/util/*.class"/>

                <exclude name="java/util/Calendar*.class"/>

            </fileset>

        </jar>

    Also, change the clean target to remove collections.jar instead of

    jconsole.jar.

    Now edit project.xml file. NetBeans uses an internal name and a

    user-visible name, both of which should be changed:

        <name>Collections</name> <!-- Customized -->

        <property name="name">collections</property> <!-- Customized -->

    Inside of <ide-actions>, you'll see actions defined for "run" and

    "debug". The Open JDK sources don't include any interesting Collections

    demos, but leave these here for now: Chances are you'll find or create

    some collections app of your own, and want to run and or debug it.

    Now, open the Collections project in NetBeans. You'll find that it operates

    just like all the other projects.

    If/when you want to have this project run a collections demo, change the run

    target in collections/build.xml to invoke it in whatever manner is appropriate

    for the app. From NetBeans, you should be able to run and debug the app,

    including setting breakpoints in collections code.

Appendix 1: Customizations

    There are several ways to customize NetBeans projects. These projects

    share a common structure, based on common/shared.xml and

    common/make.xml. Because of that sharing, some mechanisms described

    below apply to most any project.

    Several properties can be user-defined (and several should not be

    user-defined!). There are different properties files read. Some default

    targets can be overridden.

  Property files

    When projects are started, and when when ant runs (whether from NetBeans

    or the command line), these properties files are loaded in the order

    shown:

        ${basedir}/nbproject/private/build.properties

        $HOME/.openjdk/${ant.project.name}-build.properties

        $HOME/.openjdk/build.properties

        ${basedir}/build.properties

    Recall that with ant, once a property is defined, its value cannot be

    changed, so it's "first one wins".

    To set or change a property for all your projects, put the change into

    $HOME/.openjdk/build.properties. This will affect all projects,

    regardless of how many copies of the Open JDK sources you have

    installed.

    Let's say you have 2 copies of the Open JDK sources installed on your

    machine. To set or change a property for only the jconsole projects, but

    for both of them, make the change in

    $HOME/.openjdk/${ant.project.name}-build.properties. If you wanted to

    make the change for only one of them, do it in that project's

    ${basedir}/build.properties or

    ${basedir}/nbproject/private/build.properties.

    Note that the ${basedir}/build.properties file is provided as part of

    the Open JDK sources. If you want to make a change for a particular

    project, you can do so there. To be sure that you don't ever

    accidentally check it in to the Open JDK sources, you might prefer to

    change it in ${basedir}/nbproject/private/build.properties.

  User-definable Properties

    You can provide your own definitions for the properties listed below. We

    don't recommend overriding the definitions of other properties.

    The following two properties should be set before you try to use the

    projects with NetBeans or ant:

    * bootstrap.jdk

        Default: None. Please set this, normally in

        $HOME/.openjdk/build.properties.

    * jtreg.home

        Default: None. Please set this, normally in

        $HOME/.openjdk/build.properties.

    These options are for configuring the behavior of make:

    * use.make

        Default: Not set. Set this, normally in ${basedir}/build.properties,

        for a project which is make-based.