It's pretty straightforward to setup debugging for the GWT project from Eclipse. Here are the steps below:
Install Instructions
1. Install the Eclipse GWT plugin using the appropriate update site URL:
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4. Click on the "GWT" tab and set the browser "URL" as UserPhonebookSearch.html
Notes
More info on the Eclipse GWT Plugin http://code.google.com/eclipse/docs/users_guide.html
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