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Cross-Compilation Options

By default, classes are compiled against the bootstrap and extension classes of the platform that javac shipped with. But javac also supports cross-compiling, where classes are compiled against a bootstrap and extension classes of a different Java platform implementation. It is important to use the -bootclasspath and -extdirs options when cross-compiling.

-target version

Generates class files that target a specified release of the virtual machine. Class files will run on the specified target and on later releases, but not on earlier releases of the JVM. Valid targets are 1.1, 1.2, 1.3, 1.4, 1.5 (also 5), 1.6 (also 6), 1.7 (also 7), and 1.8 (also 8).

The default for the -target option depends on the value of the -source option:

If the -source option is not specified, then the value of the -target option is 1.8

If the -source option is 1.2, then the value of the -target option is 1.4

If the -source option is 1.3, then the value of the -target option is 1.4

If the -source option is 1.5, then the value of the -target option is 1.8

If the -source option is 1.6, then the value of the -target is option 1.8

If the -source option is 1.7, then the value of the -target is option 1.8

For all other values of the -source option, the value of the -target option is the value of the -source option.

-bootclasspath bootclasspath

Cross-compiles against the specified set of boot classes. As with the user class path, boot class path entries are separated by colons (:) and can be directories, JAR archives, or ZIP archives.