Change from OpenJDK to Sun JDK

From Wiki

OpenJDK is an effort to put java open source (GPL "enabled"), but the JVM is not yet robust Sun JVM.

So if you want to change follow these steps:

Install Sun Java Runtime Environment

# sudo apt-get install sun-java6-bin  sun-java6-fonts  sun-java6-jre sun-java6-plugin  


Change from OpenJRE to Sun JRE

# cd /etc/alternatives

Creating backup

# sudo mv java java_old
# sudo mv mozilla-javaplugin.so mozilla-javaplugin.so.old

Creating Symbolic links

# sudo ln -s /usr/lib/jvm/java-6-sun/jre/bin/java java
# sudo ln -s /usr/lib/jvm/java-6-sun/jre/lib/i386/libnpjp2.so mozilla-javaplugin.so

Restart your firefox and test accessing http://java.com/en/download/help/testvm.xml or http://www.javatester.org/version.html