11.4 Java

Automake provides some minimal support for Java compilation with the `JAVA' primary.

Any `.java' files listed in a `_JAVA' variable will be compiled with JAVAC at build time. By default, `.class' files are not included in the distribution.

Currently Automake enforces the restriction that only one `_JAVA' primary can be used in a given `Makefile.am'. The reason for this restriction is that, in general, it isn't possible to know which `.class' files were generated from which `.java' files -- so it would be impossible to know which files to install where. For instance, a `.java' file can define multiple classes; the resulting `.class' file names cannot be predicted without parsing the `.java' file.

There are a few variables which are used when compiling Java sources:

JAVAC

The name of the Java compiler. This defaults to `javac'.

JAVACFLAGS

The flags to pass to the compiler. This is considered to be a user variable (see section 2.5 Variables reserved for the user).

AM_JAVACFLAGS

More flags to pass to the Java compiler. This, and not JAVACFLAGS, should be used when it is necessary to put Java compiler flags into `Makefile.am'.

JAVAROOT

The value of this variable is passed to the `-d' option to javac. It defaults to `$(top_builddir)'.

CLASSPATH_ENV

This variable is an sh expression which is used to set the CLASSPATH environment variable on the javac command line. (In the future we will probably handle class path setting differently.)