I\'m using Ant 1.7.0 and installed java 1.6 which is in JAVA_HOME.
I want to build a project using java 1.5, so I\'ve exported JAVA_HOME to be my java 1.5 directory.
You can also specify in a javac task what level of compatibility ( 1.4, 1.5, 1.6 ) you want to use, you can set the "source" and "target" level values, check the docs here : Javac task documentation