Eclipse internal error while initializing Java tooling
Solution 1:
Close all open projects and exit Eclipse. Now you can open Eclipse without getting the error. Start opening your projects one by one to find which one causes the problem. This is most likely because you deleted a Device profile inside the AVD manager.
Or you can start working on a new workspace, (i.e. change your workspace), then try to import your project from the old workspace
Solution 2:
Delete your existing workspace and then recreate the workspace and add your projects.