Having imported an existing GWT project into Eclipse, the WEB-INF/lib directory was empty and had a red “X”. I knew that this project uses GAE, so..
I went to project properties -> Google -> Web Toolkit, and specified the GWT SDk to import. Eclipse copied the servlet.jar into the /lib dir.
Then I did the same thing for GAE, specifying the GAE SDK. A selection of Jars were copied to the /lib dir.
After building, the red X disappeared, project is working, but I would like to know for the future, how to intelligently identify which jars are missing, and how to ensure that they are all copied to the war before deploy? (There was nothing in the error log or console.) I was able to remedy this problem, only because I knew it needed the GWT and GAE sdks. What was a bit disturbing about this, was that the SDKs were already specified in the menu, just not copied to the WAR. I had to select different versions of the same sdk in another part of fs for import.
Is this something that should be handled automatically during build, assuming that the correct jars are in the system classpath? This seems like it could be a GPE bug, because I verified that the (other) sdks that were originally selected are in filesystem and same size/version. I have no idea why they were not copied. Tried restart, and refresh project, did nothing.
In eclipse higher than Helios releases you can use “deployment assembly ” in project properties to be sure to copy every jar into your war file.