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.TH "JAVAC" "1" "2019" "JDK 13" "JDK Commands"

.hy

.SH NAME

.PP

javac \- read Java declarations and compile them into class files

.SH SYNOPSIS

.PP

\f[CB]javac\f[R] [\f[I]options\f[R]] [\f[I]sourcefiles\-or\-classnames\f[R]]

.TP

.B \f[I]options\f[R]

Command\-line options.

.RS

.RE

.TP

.B \f[I]sourcefiles\-or\-classnames\f[R]

Source files to be compiled (for example, \f[CB]Shape.java\f[R]) or the

names of previously compiled classes to be processed for annotations

(for example, \f[CB]geometry.MyShape\f[R]).

.RS

.RE

.SH DESCRIPTION

.PP

The \f[CB]javac\f[R] command reads \f[I]source files\f[R] that contain

module, package and type declarations written in the Java programming

language, and compiles them into \f[I]class files\f[R] that run on the

Java Virtual Machine.

.PP

The \f[CB]javac\f[R] command can also \f[B]process annotations\f[R] in Java

source files and classes.

.PP

Source files must have a file name extension of \f[CB]\&.java\f[R].

Class files have a file name extension of \f[CB]\&.class\f[R].

Both source and class files normally have file names that identify the

contents.

For example, a class called \f[CB]Shape\f[R] would be declared in a source

file called \f[CB]Shape.java\f[R], and compiled into a class file called

\f[CB]Shape.class\f[R].

.PP

There are two ways to specify source files to \f[CB]javac\f[R]:

.IP \[bu] 2

For a small number of source files, you can list their file names on the

command line.

.IP \[bu] 2

For a large number of source files, you can use the

\f[CB]\@\f[R]\f[I]filename\f[R] option on the command line to specify an

\f[I]argument file\f[R] that lists their file names.

See \f[B]Standard Options\f[R] for a description of the option and

\f[B]Command\-Line Argument Files\f[R] for a description of

\f[CB]javac\f[R] argument files.

.PP

The order of source files specified on the command line or in an

argument file is not important.

\f[CB]javac\f[R] will compile the files together, as a group, and will

automatically resolve any dependencies between the declarations in the

various source files.

.PP

\f[CB]javac\f[R] expects that source files are arranged in one or more

directory hierarchies on the file system, described in \f[B]Arrangement

of Source Code\f[R].

.PP

To compile a source file, \f[CB]javac\f[R] needs to find the declaration

of every class or interface that is used, extended, or implemented by

the code in the source file.

This lets \f[CB]javac\f[R] check that the code has the right to access

those classes and interfaces.

Rather than specifying the source files of those classes and interfaces

explicitly, you can use command\-line options to tell \f[CB]javac\f[R]

where to search for their source files.

If you have compiled those source files previously, you can use options

to tell \f[CB]javac\f[R] where to search for the corresponding class

files.

The options, which all have names ending in "path", are described in

\f[B]Standard Options\f[R], and further described in \f[B]Configuring a

Compilation\f[R] and \f[B]Searching for Module, Package and Type

Declarations\f[R].

.PP

By default, \f[CB]javac\f[R] compiles each source file to a class file in

the same directory as the source file.

However, it is recommended to specify a separate destination directory

with the \f[CB]\-d\f[R] option described in \f[B]Standard Options\f[R].

.PP

Command\-line \f[B]options\f[R] and \f[B]environment variables\f[R] also

control how \f[CB]javac\f[R] performs various tasks:

.IP \[bu] 2

Compiling code to run on earlier releases of the JDK.

.IP \[bu] 2

Compiling code to run under a debugger.

.IP \[bu] 2

Checking for stylistic issues in Java source code.

.IP \[bu] 2

Checking for problems in \f[CB]javadoc\f[R] comments

(\f[CB]/**\ ...\ */\f[R]).

.IP \[bu] 2

Processing annotations in source files and class files.

.IP \[bu] 2

Upgrading and patching modules in the compile\-time environment.

.PP

\f[CB]javac\f[R] supports \f[B]Compiling for Earlier Releases Of The

Platform\f[R] and can also be invoked from Java code using one of a

number of \f[B]APIs\f[R]

.SH OPTIONS

.PP

\f[CB]javac\f[R] provides \f[B]standard options\f[R], and \f[B]extra

options\f[R] that are either non\-standard or are for advanced use.

.PP

Some options take one or more arguments.

If an argument contains spaces or other whitespace characters, the value

should be quoted according to the conventions of the environment being

used to invoke javac.

If the option begins with a single dash (\f[CB]\-\f[R]) the argument

should either directly follow the option name, or should be separated

with a colon (\f[CB]:\f[R]) or whitespace, depending on the option.

If the option begins with a double dash (\f[CB]\-\-\f[R]), the argument

may be separated either by whitespace or by an equals (\f[CB]=\f[R])

character with no additional whitespace.

For example,

.IP

.nf

\f[CB]

\-Aname="J.\ Duke"

\-proc:only

\-d\ myDirectory

\-\-module\-version\ 3

\-\-module\-version=3

\f[R]

.fi

.PP

In the following lists of options, an argument of \f[I]path\f[R]

represents a search path, composed of a list of file system locations

separated by the platform path separator character, (semicolon

\f[CB];\f[R] on Windows, or colon \f[CB]:\f[R] on other systems.) Depending

on the option, the file system locations may be directories, JAR files

or JMOD files.

.SS Standard Options

.TP

.B \f[CB]\@\f[R]\f[I]filename\f[R]

Reads options and file names from a file.

To shorten or simplify the \f[CB]javac\f[R] command, you can specify one

or more files that contain arguments to the \f[CB]javac\f[R] command

(except \f[CB]\-J\f[R] options).

This lets you to create \f[CB]javac\f[R] commands of any length on any

operating system.

See \f[B]Command\-Line Argument Files\f[R].

.RS

.RE

.TP

.B \f[CB]\-A\f[R]\f[I]key\f[R][\f[CB]=\f[R]\f[I]value\f[R]]

Specifies options to pass to annotation processors.

These options are not interpreted by \f[CB]javac\f[R] directly, but are

made available for use by individual processors.

The \f[I]key\f[R] value should be one or more identifiers separated by a

dot (\f[CB]\&.\f[R]).

.RS

.RE

.TP

.B \f[CB]\-\-add\-modules\f[R] \f[I]module\f[R]\f[CB],\f[R]\f[I]module\f[R]

Specifies root modules to resolve in addition to the initial modules, or

all modules on the module path if \f[I]module\f[R] is

\f[CB]ALL\-MODULE\-PATH.\f[R]

.RS

.RE

.TP

.B \f[CB]\-\-boot\-class\-path\f[R] \f[I]path\f[R] or \f[CB]\-bootclasspath\f[R] \f[I]path\f[R]

Overrides the location of the bootstrap class files.

.RS

.PP

\f[B]Note:\f[R] This can only be used when compiling for releases prior

to JDK 9.

As applicable, see the descriptions in \f[CB]\-\-release\f[R],

\f[CB]\-source\f[R], or \f[CB]\-target\f[R] for details.

For JDK 9 or later, see \f[CB]\-\-system\f[R].

.RE

.TP

.B \f[CB]\-\-class\-path\f[R] \f[I]path\f[R], \f[CB]\-classpath\f[R] \f[I]path\f[R], or \f[CB]\-cp\f[R] \f[I]path\f[R]

Specifies where to find user class files and annotation processors.

This class path overrides the user class path in the \f[CB]CLASSPATH\f[R]

environment variable.

.RS

.IP \[bu] 2

If \f[CB]\-\-class\-path\f[R], \f[CB]\-classpath\f[R], or \f[CB]\-cp\f[R] are

not specified, then the user class path is the value of the

\f[CB]CLASSPATH\f[R] environment variable, if that is set, or else the

current directory.

.IP \[bu] 2

If not compiling code for modules, if the \f[CB]\-\-source\-path\f[R] or

\-sourcepath` option is not specified, then the user class path is also

searched for source files.

.IP \[bu] 2

If the \f[CB]\-processorpath\f[R] option is not specified, then the class

path is also searched for annotation processors.

.RE

.TP

.B \f[CB]\-d\f[R] \f[I]directory\f[R]

Sets the destination directory (or \f[I]class output directory\f[R]) for

class files.

If a class is part of a package, then \f[CB]javac\f[R] puts the class file

in a subdirectory that reflects the module name (if appropriate) and

package name.

The directory, and any necessary subdirectories, will be created if they

do not already exist.

.RS

.PP

If the \f[CB]\-d\f[R] option is not specified, then \f[CB]javac\f[R] puts

each class file in the same directory as the source file from which it

was generated.

.PP

Except when compiling code for multiple modules, the contents of the

class output directory will be organized in a package hierarchy.

When compiling code for multiple modules, the contents of the output

directory will be organized in a module hierarchy, with the contents of

each module in a separate subdirectory, each organized as a package

hierarchy.

.PP

\f[B]Note:\f[R] When compiling code for one or more modules, the class

output directory will automatically be checked when searching for

previously compiled classes.

When not compiling for modules, for backwards compatibility, the

directory is \f[I]not\f[R] automatically checked for previously compiled

classes, and so it is recommended to specify the class output directory

as one of the locations on the user class path, using the

\f[CB]\-\-class\-path\f[R] option or one of its alternate forms.

.RE

.TP

.B \f[CB]\-deprecation\f[R]

Shows a description of each use or override of a deprecated member or

class.

Without the \f[CB]\-deprecation\f[R] option, \f[CB]javac\f[R] shows a

summary of the source files that use or override deprecated members or

classes.

The \f[CB]\-deprecation\f[R] option is shorthand for

\f[CB]\-Xlint:deprecation\f[R].

.RS

.RE

.TP

.B \f[CB]\-\-enable\-preview\f[R]

Enables preview language features.

Used in conjunction with either \f[CB]\-source\f[R] or

\f[CB]\-\-release\f[R].

.RS

.RE

.TP

.B \f[CB]\-encoding\f[R] \f[I]encoding\f[R]

Specifies character encoding used by source files, such as EUC\-JP and

UTF\-8.

If the \f[CB]\-encoding\f[R] option is not specified, then the platform

default converter is used.

.RS

.RE

.TP

.B \f[CB]\-endorseddirs\f[R] \f[I]directories\f[R]

Overrides the location of the endorsed standards path.

.RS

.PP

\f[B]Note:\f[R] This can only be used when compiling for releases prior

to JDK 9.

As applicable, see the descriptions in \f[CB]\-\-release\f[R],

\f[CB]\-source\f[R], or \f[CB]\-target\f[R] for details.

.RE

.TP

.B \f[CB]\-extdirs\f[R] \f[I]directories\f[R]

Overrides the location of the installed extensions.

\f[CB]directories\f[R] is a list of directories, separated by the platform

path separator (\f[CB];\f[R] on Windows, and \f[CB]:\f[R] otherwise).

Each JAR file in the specified directories is searched for class files.

All JAR files found become part of the class path.

.RS

.PP

If you are compiling for a release of the platform that supports the

Extension Mechanism, then this option specifies the directories that

contain the extension classes.

See [Compiling for Other Releases of the Platform].

.PP

\f[B]Note:\f[R] This can only be used when compiling for releases prior

to JDK 9.

As applicable, see the descriptions in \f[CB]\-\-release\f[R],

\f[CB]\-source\f[R], or \f[CB]\-target\f[R] for details.

.RE

.TP

.B \f[CB]\-g\f[R]

Generates all debugging information, including local variables.

By default, only line number and source file information is generated.

.RS

.RE

.TP

.B \f[CB]\-g:\f[R][\f[CB]lines\f[R], \f[CB]vars\f[R], \f[CB]source\f[R]]

Generates only the kinds of debugging information specified by the

comma\-separated list of keywords.

Valid keywords are:

.RS

.TP

.B \f[CB]lines\f[R]

Line number debugging information.

.RS

.RE

.TP

.B \f[CB]vars\f[R]

Local variable debugging information.

.RS

.RE

.TP

.B \f[CB]source\f[R]

Source file debugging information.

.RS

.RE

.RE

.TP

.B \f[CB]\-g:none\f[R]

Does not generate debugging information.

.RS

.RE

.TP

.B \f[CB]\-h\f[R] \f[I]directory\f[R]

Specifies where to place generated native header files.

.RS

.PP

When you specify this option, a native header file is generated for each

class that contains native methods or that has one or more constants

annotated with the \f[B]\f[BC]java.lang.annotation.Native\f[B]\f[R]

annotation.

If the class is part of a package, then the compiler puts the native

header file in a subdirectory that reflects the module name (if

appropriate) and package name.

The directory, and any necessary subdirectories, will be created if they

do not already exist.

.RE

.TP

.B \f[CB]\-\-help\f[R], \f[CB]\-help\f[R] or \f[CB]\-?\f[R]

Prints a synopsis of the standard options.

.RS

.RE

.TP

.B \f[CB]\-\-help\-extra\f[R] or \f[CB]\-X\f[R]

Prints a synopsis of the set of extra options.

.RS

.RE

.TP

.B \f[CB]\-implicit:\f[R][\f[CB]none\f[R], \f[CB]class\f[R]]

Specifies whether or not to generate class files for implicitly

referenced files:

.RS

.IP \[bu] 2

\f[CB]\-implicit:class\f[R] \-\-\- Automatically generates class files.

.IP \[bu] 2

\f[CB]\-implicit:none\f[R] \-\-\- Suppresses class file generation.

.PP

If this option is not specified, then the default automatically

generates class files.

In this case, the compiler issues a warning if any class files are

generated when also doing annotation processing.

The warning is not issued when the \f[CB]\-implicit\f[R] option is

explicitly set.

See \f[B]Searching for Module, Package and Type Declarations\f[R].

.RE

.TP

.B \f[CB]\-J\f[R]\f[I]option\f[R]

Passes \f[I]option\f[R] to the runtime system, where \f[I]option\f[R] is

one of the Java options described on \f[B]java\f[R] command.

For example, \f[CB]\-J\-Xms48m\f[R] sets the startup memory to 48 MB.

.RS

.PP

\f[B]Note:\f[R] The \f[CB]CLASSPATH\f[R] environment variable,

\f[CB]\-classpath\f[R] option, \f[CB]\-bootclasspath\f[R] option, and

\f[CB]\-extdirs\f[R] option do not specify the classes used to run

\f[CB]javac\f[R].

Trying to customize the compiler implementation with these options and

variables is risky and often does not accomplish what you want.

If you must customize the compiler implementation, then use the

\f[CB]\-J\f[R] option to pass options through to the underlying Java

launcher.

.RE

.TP

.B \f[CB]\-\-limit\-modules\f[R] \f[I]module\f[R]\f[CB],\f[R]\f[I]module\f[R]*

Limits the universe of observable modules.

.RS

.RE

.TP

.B \f[CB]\-\-module\f[R] \f[I]module\-name\f[R] (\f[CB],\f[R]\f[I]module\-name\f[R])* or \f[CB]\-m\f[R] \f[I]module\-name\f[R] (\f[CB],\f[R]\f[I]module\-name\f[R])*

Compiles those source files in the named modules that are newer than the

corresponding files in the output directory.

.RS

.RE

.TP

.B \f[CB]\-\-module\-path\f[R] \f[I]path\f[R] or \f[CB]\-p\f[R] \f[I]path\f[R]

Specifies where to find application modules.

.RS

.RE

.TP

.B \f[CB]\-\-module\-source\-path\f[R] \f[I]module\-source\-path\f[R]

Specifies where to find source files when compiling code in multiple

modules.

See [Compilation Modes] and \f[B]The Module Source Path Option\f[R].

.RS

.RE

.TP

.B \f[CB]\-\-module\-version\f[R] \f[I]version\f[R]

Specifies the version of modules that are being compiled.

.RS

.RE

.TP

.B \f[CB]\-nowarn\f[R]

Disables warning messages.

This option operates the same as the \f[CB]\-Xlint:none\f[R] option.

.RS

.RE

.TP

.B \f[CB]\-parameters\f[R]

Generates metadata for reflection on method parameters.

Stores formal parameter names of constructors and methods in the

generated class file so that the method

\f[CB]java.lang.reflect.Executable.getParameters\f[R] from the Reflection

API can retrieve them.

.RS

.RE

.TP

.B \f[CB]\-proc:\f[R][\f[CB]none\f[R], \f[CB]only\f[R]]

Controls whether annotation processing and compilation are done.

\f[CB]\-proc:none\f[R] means that compilation takes place without

annotation processing.

\f[CB]\-proc:only\f[R] means that only annotation processing is done,

without any subsequent compilation.

.RS

.RE

.TP

.B \f[CB]\-processor\f[R] \f[I]class1\f[R][\f[CB],\f[R]\f[I]class2\f[R]\f[CB],\f[R]\f[I]class3\f[R]...]

Names of the annotation processors to run.

This bypasses the default discovery process.

.RS

.RE

.TP

.B \f[CB]\-\-processor\-module\-path\f[R] \f[I]path\f[R]

Specifies the module path used for finding annotation processors.

.RS

.RE

.TP

.B \f[CB]\-\-processor\-path\f[R] \f[I]path\f[R] or \f[CB]\-processorpath\f[R] \f[I]path\f[R]

Specifies where to find annotation processors.

If this option is not used, then the class path is searched for

processors.

.RS

.RE

.TP

.B \f[CB]\-profile\f[R] \f[I]profile\f[R]

Checks that the API used is available in the specified profile.

.RS

.PP

\f[B]Note:\f[R] This can only be used when compiling for releases prior

to JDK 9.

As applicable, see the descriptions in \f[CB]\-\-release\f[R],

\f[CB]\-source\f[R], or \f[CB]\-target\f[R] for details.

.RE

.TP

.B \f[CB]\-\-release\f[R] \f[I]release\f[R]

Compiles source code according to the rules of the Java programming

language for the specified Java SE release, generating class files which

target that release.

Source code is compiled against the combined Java SE and JDK API for the

specified release.

.RS

.PP

The supported values of \f[I]release\f[R] are the current Java SE release

and a limited number of previous releases, detailed in the command\-line

help.

.PP