[xhhuang@node3 Desktop]$ sudo alternatives --config java[sudo] password for xhhuang: There is 1 program that provides 'java'.  Selection    Command-----------------------------------------------*+ 1           /usr/lib/jvm/jre-1.5.0-gcj/bin/javaEnter to keep the current selection[+], or type selection number: 1[xhhuang@node3 Desktop]$ ls -l /usr/java/total 4lrwxrwxrwx 1 root root   16 Jul  9 18:37 default -> /usr/java/latestdrwxr-xr-x 8 root root 4096 Jul  9 18:37 jdk1.7.0_67lrwxrwxrwx 1 root root   21 Jul  9 18:37 latest -> /usr/java/jdk1.7.0_67[xhhuang@node3 Desktop]$ sudo alternatives --install /usr/bin/java java /usr/java/jdk1.7.0_67/bin/java 3 --slave /usr/bin/javac javac /usr/java/jdk1.7.0_67/bin/java[xhhuang@node3 Desktop]$ sudo alternatives --config javaThere are 2 programs which provide 'java'.  Selection    Command-----------------------------------------------*+ 1           /usr/lib/jvm/jre-1.5.0-gcj/bin/java   2           /usr/java/jdk1.7.0_67/bin/javaEnter to keep the current selection[+], or type selection number: 2[xhhuang@node3 Desktop]$ java -versionjava version "1.7.0_67"Java(TM) SE Runtime Environment (build 1.7.0_67-b01)Java HotSpot(TM) 64-Bit Server VM (build 24.65-b04, mixed mode)[xhhuang@node3 Desktop]$ touch note.txt[xhhuang@node3 Desktop]$ sudo alternatives --config javasudo alternatives --install /usr/bin/java java /usr/java/jdk1.7.0_67/bin/java 3 --slave /usr/bin/javac javac /usr/java/jdk1.7.0_67/bin/java