Hello Gowtham,
The error message given is due to JDK mismatch between your java application and the java version of PI server. SAP PI uses JDK 1.4 or 1.6 by default, depending of PI version, so you should use the same JDK in your mapping program as well.
In your Eclipse IDE, double click on your project > Build Path > Configure Build Path and point it to a correct java library.
Regards,
Arthur Silva