You may feel this is a duplicated question, but none of the questions with the same title solve my problems. I am using Jersey 2.0 creating a RESTful web service in Eclipse,
I guess this has already been answered, but just wanted to add an extra tip.
For web projects in Eclipse, it is almost always advisable to manage dependencies with Maven. Use a Maven plugin like m2e. Once you add a dependency to your Maven project, it should automatically deploy those libraries to WEB-INF/lib. If it does not (for whatever reasons), you can explicit do so:
This should add the libraries to WEB-INF/lib, although you'd still not see them in the Project Explorer view. But your ClassNotFoundException should go away now.