sudo update-alternatives --config java
There are 4 choices for the alternative java (providing /usr/bin/java).

  Selection    Path                                            Priority   Status
------------------------------------------------------------
  0            /usr/lib/jvm/java-6-oracle/jre/bin/java          1063      auto mode
  1            /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java   1061      manual mode
  2            /usr/lib/jvm/java-6-oracle/jre/bin/java          1063      manual mode
  3            /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java   1051      manual mode
* 4            /usr/lib/jvm/java-7-oracle/jre/bin/java          1062      manual