Fix Javac javalangOutOfMemoryError¶

When javac is compiling a large number of java source files, it may fail with java.lang.OutOfMemoryError:

The system is out of resources.
Consult the following stack trace for details.
java.lang.OutOfMemoryError: Java heap space

You just need to set environment variable ANT_OPTS:

export ANT_OPTS="-Xms256m -Xmx256m"    (ksh/bash)
setenv ANT_OPTS="-Xms256m -Xmx256m"    (tcsh/csh)
set ANT_OPTS="-Xms256m -Xmx256m"       (Windows)