Bugzilla Bug 61665

some packages, most notably, dev-java/ant, provide their own shell script
launcher which uses java-config to obtain JAVA_HOME. This is annoying as I
cannot simply specify "JAVA_HOME=<path> ant", but instead must use java-config
or as I have done, hack the ant launcher to respect the environment and not set
JAVA_HOME if its already set.

This would be a nice bit of common functionality to extract to a java the
java-utils eclass.

My hack follows (this is from /usr/bin/ant from dev-java/ant)
BEFORE:
if [ -f $HOME/.gentoo/java-env ] ; then
  source $HOME/.gentoo/java-env
else
  JAVA_HOME=`java-config --jdk-home`
  CLASSPATH=`java-config --classpath`:${CLASSPATH}
fi

if [ -z $JAVA_HOME ] ; then
  echo "Error: No JDK found!"
  echo "Try using java-config script to set your JDK"
  echo "Remember that you need a JDK not a JRE"
  exit 1
fi

FIX:
wrap the above with a conditional "if [ -z $JAVA_HOME ]; then"
and respect a previously declared JAVA_HOME

Thanks

*** Bug 64282 has been marked as a duplicate of this bug. ***

This seems to have been fixed already. Now, JAVA_HOME will only be defined if 
it hasn't already been so.