How do I fix run time errors?

From ggc

I just finished making new methods to shorten the advance frame method of my program and everything appears to compile. However, I am experiencing a run time error that I cannot fix. I think my error is in the advance frame,but I don't know enough about run time errors to correct the program. What are common items that would cause a run time error?

Answer

What you do is take a look at the output in the small text box that should appear below your game. This information is called the exception. Each line in the exception shows the class and line number of the error. Find the topmost line that contains a class you wrote (there will be many others you did not write probably that start with java. or fang.). This is the line that caused the problem. If this does not entirely help you figure out the problem, talk to me in class today and I'll help you figure it out.