The alternatives command is used for maintained symbolic links.

This command used to creates, removes, maintains and displays information about the symbolic links comprising the alternatives system. Let’s use the alternatives command to configure Java on your system. 

$ sudo alternatives --config java

There are 2 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
*+ 1           /usr/lib/jvm/jre-1.7.0-openjdk.x86_64/bin/java
   2           /usr/lib/jvm/jre-1.8.0-openjdk.x86_64/bin/java

Enter to keep the current selection[+], or type selection number: 2