Excluding Proposals from Code Completion in NetBeans 8
By Geertjan on Jan 22, 2014
Therefore, in NetBeans 8, you can exclude the classes you don't need right from within the Code Completion box. Below, notice the lightbulb at the far right in the currently selected item in the Code Completion box, which appears the second time you call up code completion:
Press Alt-Enter or click the lightbulb and now you see this:
Press Enter and the item is excluded from the Code Completion box because it has now been added here for you, i.e., instead of going all the way here, the class was registered here for you when you pressed Enter above:
NetBeans 8. Making your coding life simpler all the time.