Setting setNeedsDisplay or setNeedsDisplayInRect properly

Question

I have a Utility App which puts up a UIView which displays correctly the first time from the nib. Then I float several additional UIViews above that layer and manipulate them. Each of those is issued a setNeedsDisplay whenever I change the underlying type which either needs a new image, or to set the current image with self.hidden = YES;
I also have a routine which updates a counter which resides as a graphic on the main UIView. For that, the initial image shows up just fine, but all updates, set by a single update routine that changes the image in a small rectangle (36x16) and then calls [self setNeedsDisplayInRect:myRect];as soon as the update has drawn the new images.
In both cases, the updates do not seem to be happening.
Am i missing something?
I thought not, since the redrawing of the UIViews which are layered above the main UIView and are subviews of the mainView work just fine.
As a last ditch thing to try, I decided to remove mainView from its superview (the window) and immediately add it back to the window as a subview. Maybe i should also do a retain in between just to make sure it doesn't go away on me, but the current code is
UIView* mySuper = mainView.superview;
// [mainView retain]; // is this needed?
[mainView removeFromSuperview];
[mySuper addSubview:mainView];
// [mainView release]; // in case retain is needed
So, what gives? Why does the setNeedsDisplay code work on the subview UIViews, but seems to be ignored on the main MainView UIView?
In an early test case, I tried using setNeedsDisplay instead of setNeedsDisplayInRect for the counter, and it started drawing the counter at the wrong place on the screen, and only updating every so many increments at the correct location. Hence, the change to setNeedsDisplayInRect.

Answer 1

Your PATH is exactly what it should be.
The CLASSPATH answer depends on where you're compiling and running.
If you're doing things on the command line, I think the right answer is to use the -classpath option on javac.exe and java.exe.
If you're using NetBeans or another IDE, the right answer is to add JARs and paths according to the idiom demanded by the IDE. Each one is different, and all the ones I know of ignore the system CLASSPATH environment variable. I don't have one set on my machine.