javac - Java Compilation Command and Options

This section describes what are the commonly used command line options for the Java compiler - 'javac' tool.

What Is "javac"? "javac" is a command line tool that reads Java source files and compiles them into bytecode class files.

"javac" has been included in JDK installation since JDK 1.0. And it is represented by the %java_home%\bin\javac.exe program file.

"javac" has the following syntax:

javac [options] [sourcefiles]

where "options" is a list of options and "sourcefiles" is a list of Java source files.

Commonly used "javac" options are:

You can run "javac" by typing in "jmc" at the command prompt, if you have %java_home%\bin directory included in "path" the environment variable. If the "javac" command is executed without any options, it will display the quick usage information as shown below:

C:\herong>javac

Usage: javac <options> <source files>
where possible options include:
  @<filename>               Read options and filenames from file
  -Akey[=value]             Options to pass to annotation processors
  --add-modules <module>(,<module>)*
        Root modules to resolve in addition to the initial modules, or 
        all modules on the module path if <module> is ALL-MODULE-PATH.
  --boot-class-path <path>, -bootclasspath <path>
        Override location of bootstrap class files
  --class-path <path>, -classpath <path>, -cp <path>
        Specify where to find user class files and annotation processors
  -d <directory>            Specify where to place generated class files
  -deprecation
        Output source locations where deprecated APIs are used
  -encoding <encoding>      Specify character encoding used by source files
  -endorseddirs <dirs>      Override location of endorsed standards path
  -extdirs <dirs>           Override location of installed extensions
  -g                        Generate all debugging info
  -g:{lines,vars,source}    Generate only some debugging info
  -g:none                   Generate no debugging info
  -h <directory>
        Specify where to place generated native header files
  --help, -help             Print this help message
  --help-extra, -X          Print help on extra options
  -implicit:{none,class}
        Specify whether or not to generate class files for implicitly 
        referenced files
  -J<flag>                  Pass <flag> directly to the runtime system
  --limit-modules <module>(,<module>)*
        Limit the universe of observable modules
  --module <module-name>, -m <module-name>
        Compile only the specified module, check timestamps
  --module-path <path>, -p <path>
        Specify where to find application modules
  --module-source-path <module-source-path>
        Specify where to find input source files for multiple modules
  --module-version <version>
        Specify version of modules that are being compiled
  -nowarn                   Generate no warnings
  -parameters
        Generate metadata for reflection on method parameters
  -proc:{none,only}
        Control whether annotation processing and/or compilation is done.
  -processor <class1>[,<class2>,<class3>...]
        Names of the annotation processors to run; bypasses default 
        discovery process
  --processor-module-path <path>
        Specify a module path where to find annotation processors
  --processor-path <path>, -processorpath <path>
        Specify where to find annotation processors
  -profile <profile>
        Check that API used is available in the specified profile
  --release <release>
        Compile for a specific VM version. Supported targets: 
        10, 6, 7, 8, 9
  -s <directory>            Specify where to place generated source files
  -source <release>
        Provide source compatibility with specified release
  --source-path <path>, -sourcepath <path>
        Specify where to find input source files
  --system <jdk>|none       Override location of system modules
  -target <release>         Generate class files for specific VM version
  --upgrade-module-path <path>
        Override location of upgradeable modules
  -verbose                  
        Output messages about what the compiler is doing
  --version, -version       Version information
  -Werror                   Terminate compilation if warnings occur

For more information, see "javac" reference page at https://docs.oracle.com/javase/10/tools/javac.htm.

Last update: 2018.

Table of Contents

 About This Book

 Java Tools Terminology

 Java Tools Included in JDK

javac - The Java Program Compiler

javac - Java Compilation Command and Options

 Compiling Hello.java - My First Java Program

 "javac -classpath" - Specifying Class Path

 "javac -verbose" - Printing Compilation Details

 "javac -sourcepath" - Specifying Source Path

 "javac -d" - Specifying Output Directory

 Two Types of "import" Statements

 "import" Statements Processed by "javac"

 "javac -g" - Controlling Debugging Information

 "javac --module" - Compiling Entire Module

 "javac -X" - Specifying Non-Standard Options

 jar - The JAR File Tool

 jlink - The JRE Linker

 jmod - The JMOD File Tool

 jimage - The JIMAGE File Tool

 java - The Java Program Launcher

 jdb - The Java Debugger

 jcmd - The JVM Diagnostic Tool

 jconsole - Java Monitoring and Management Console

 jstat - JVM Statistics Monitoring Tool

 JVM Troubleshooting Tools

 jvisualvm (Java VisualVM) - JVM Visual Tool

 jmc - Java Mission Control

 javap - The Java Class File Disassembler

 keytool - Public Key Certificate Tool

 jarsigner - JAR File Signer

 jshell - Java Language Shell

 native2ascii - Native-to-ASCII Encoding Converter

 Outdated Tutorials

 References

 Full Version in PDF/EPUB