If you have multiple versions of Java on your Mac, you can set the current working version from the command line as follows:
export JAVA_HOME=`/usr/libexec/java_home -v1.6`
This will set the version to 1.6. You can of course see the current version with
java -version
You can see all java versions installed on your mac with:
/usr/libexec/java_home -V
(tested with macos 10.8.4 )
