Appendable Cannot be resolved to a type

This is one error which I encountered immediately after setting up Development environment.
Error:
Appendable Cannot be resolved to a type.I got in projects like BusinessServices,Party etc.

Resolution:

Go to the buildpath of the project which is having this error.
Libraries tab->Remove the JRE system library.

Then click Add Library

Select JRE system library ,Next ->Workspace default finish.

Do the same for each project which is having this compile error.