You can also easily choose which Java SDK is good for you; see
[root@mysys java]# update-alternatives --config java
There are 4 programs which provide 'java'.
Selection Command
-----------------------------------------------
1 /usr/lib/jvm/jre-1.4.2-gcj/bin/java
+ 2 /usr/local/queuemetrics/jdk1.5.0_11/bin/java
3 /usr/lib/jvm/jre-1.6.0-openjdk/bin/java
* 4 /usr/lib/jvm/jre-1.7.0-openjdk/bin/java
Enter to keep the current selection[+], or type selection number:
So you can easily go back to the default JDK if you need to.