Ubuntu14.04 切换jdk1.6和open jdk1.7编译环境
sudo update-alternatives --install /usr/bin/java java /usr/lib/java/jdk1.6.0_41/bin/java 300 sudo update-alternatives --install /usr/bin/javac javac /usr/lib/java/jdk1.6.0_41/bin/javac 300
