Java on Fedora 15

Hi all,
I need to install and run Java 6 on Fedora 15.I did installed it on Fedora 15 as per the guidelines,but I faced a problem.I could easily compile my classes ,but could not run them.The error i got was 'NoClassDefFound'.Why is this happening?
Please guide me through.

Thanks.......

Which Java 6? The one from Oracle? Or OpenJDK?

First, verify that the JDK installed properly. Run "java -version" and make sure that it reports the version you installed.

Second, we need to know the classpath you used to run the app, and the name of the missing class. Also the location of where you believe the class resides would help.

Hi,
I am using the java from oracle,i.e Java SE(6).I may have some trouble regarding the classpath though.So please guide me through the correct and precise steps.
Thanks....

Hi all,
I just figured out what was going wrong.It was the classpath,which should be
export JAVA_HOME=export JAVA_HOME="/usr/java/jdk1.7.0_02"

after installing JDK 7 and adding this line in /etc/profile i got my classes compiled and executed.