Prablem with adding External library in WebDynpro DC's

Hi.

I have created the external library for the .jar file. and also created two public part namley compilation and assembly.

But when i used these public part in my webdynpro DC and alos added jar file in 'Java build path', it giving error like

The project was not built since its classpath is incomplete. Cannot find the class file for

java.lang.Object. Fix the classpath then try rebuilding this project.

LocalDevelopment_jxlgensap.com

This compilation unit indirectly references the missing type java.lang.Object

(typically some required class file is referencing a type outside the classpath)

InternalJxlWindInterfaceView.java LocalDevelopment_jxlgensap.com/gen_wdp/packages/com/sap/wdp

Could you please rectify the issue asap.

thanks

Arun