It's a trick to increasing your productivity in using Eclipse to develope Java code, also apply to Android programming. For example, you want to override the method finish(), but you forget the spelling, or you are too laze to type it. Right click on any space on your source code, and invoke Source > Override/Implement Methods.
Select the desired method(s) to be inserted, also you can select the insertion point, click OK.
See, your code have been inserted.
It's a very useful and helpful practice for me.