Select the Edit Source Lookup... command [ ] to open the Source Path Dialog, which allows you to make changes to the source lookup path of the selected debug target.
The Source Path Dialog:
Debugger Local debugging Remote debugging
Changing debugger launch options Connecting to a remote VM with the Remote Java application launch configuration Disconnecting from a VM Launching a Java program Preparing to debug Resuming the execution of suspended threads Running and debugging Stepping through the execution of a program Suspending threads
Debug View Debug preferences