Bug 34754 Array out of bounds in code assist
Build: 2.1 RC2 I got into a state when invoking code assist where the popup window was empty. I can't reproduce it, but I was typing while the popup was open. When I entered a character that narrowed down the possible search values to zero, I was left with an empty popup window. In my case I had entered resource.getK (and there are no methods starting with "getk" on IResource). This resulted in an ArrayIndexOutOfBoundsException in the log. I will attach the log.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/java/JavaCompletionProposal.java
document.addPositionUpdater(fPositionUpdater);
				document.addPosition(CATEGORY, fPosition);
			} catch (BadPositionCategoryException e) {
				
				JavaPlugin.log(e);
			}
		}
	
		/**
		 * Called after the document changed occured. It must be preceded by a call to preReplace().
		 * 
		 * @param document the document on which to track the reference position.
		 */
		public int postReplace(IDocument document) {
			try {
				document.removePosition(CATEGORY, fPosition);
				document.removePositionUpdater(fPositionUpdater);
				document.removePositionCategory(CATEGORY);
				 
			} catch (BadPositionCategoryException e) {
				
				JavaPlugin.log(e);
			}
			return fPosition.getOffset();
		}
	}	
	
	private static class ExitPolicy implements LinkedPositionUI.ExitPolicy {
		
		final char fExitCharacter;