Updating default Java executables with new executables
# update-alternatives --install <symlink of java executable> <config_name> <newer java binary> <priority>
Usage :
# update-alternatives --install "/usr/bin/java" "java" "/usr/java/default/bin/java" 3
# update-alternatives --install "/usr/bin/javac" "javac" "/usr/java/default/bin/javac" 3
# update-alternatives --install "/usr/bin/javaws" "javaws" "/usr/java/default/bin/javaws" 3