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
public ExitPolicy(char exitCharacter) {
			fExitCharacter= exitCharacter;
		}
		/*
		 * @see org.eclipse.jdt.internal.ui.text.link.LinkedPositionUI.ExitPolicy#doExit(org.eclipse.jdt.internal.ui.text.link.LinkedPositionManager, org.eclipse.swt.events.VerifyEvent, int, int)
		 */
		public ExitFlags doExit(LinkedPositionManager manager, VerifyEvent event, int offset, int length) {
			
			if (event.character == fExitCharacter) {
				if (manager.anyPositionIncludes(offset, length))
					return new ExitFlags(LinkedPositionUI.COMMIT| LinkedPositionUI.UPDATE_CARET, false);
				else
					return new ExitFlags(LinkedPositionUI.COMMIT, true);
			}	
			
			switch (event.character) {			
			case '\b':
				if (manager.getFirstPosition().length == 0)
					return new ExitFlags(0, true);
				else
					return null;
				
			case '\n':
			case '\r':
				return new ExitFlags(LinkedPositionUI.COMMIT, true);
				
			default:
				return null;
			}