Set up java sources for eclipse debugger

you sure know the situation during debugging when the thread 开发者_C百科of execution suddenly isn't backed by source code and the icon "attach sources" appears... I can't find any settings where it could be set up. I always have to wait till the previously mentioned situation happens to set it up.

Is there this configuration anywhere in preferences ? I really can't find it, thanks

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Right click on a project -> Build Path -> Libraries, look here: Is there an easy way to attach source in Eclipse?