How to find out which Java classes are missing in GWT (client side)?

Question

I am trying to import a Java library into a GWT project.

Since the client-side of GWT does not have access to the whole Java API, some classes cannot be found.

Answer 1

This link GWT JRE Emulation Reference shows the list of the classes you can use on the client side. There are out there client libraries to add missing widgets or features to the out-of-the-box API.