Apps Adding Custom Class to android framework

[mprabakar]

I have added a new class to frameworks/base/media/java/android/media/.
I have given a complete build and pushed framework.jar into my device.
But, when I tried to access the class from application, following exception is thrown:
java.lang.Noclassdeffounderror.

can someone help ?
Note: code base - android 4.2.2