Just use the JPanel to paint. Use the JFrame for interface. Don't cram it all into a JFrame just because you can only extend that class. Extend the JFrame, but create a JPanel and paint on it.

Why can't you do this? An error? If so, please post it!

Btw, if you could post your files on a site, it would be extremely helpful.

[b][U]Return-Type Methods or functions[/U][/b]
Okay, so think of functions as an ATM. You input a bunch of values, and they output one. The same is with a method or function. It must "spit-out" a number that fits its return type. It is usually used for variables.

[CODE]public double multiply(int firstVar, int SecondVar){
int product=firstVar*secondVar;
return product;

All the variables from firstVar to product were local variables specifically owned by the method or function. However, when you return a value, it becomes global to the entire class.

[b][U]Void methods or functions[/U][/b]
A type variable has to return a value, hence your
[CODE]return 0;[/CODE]
However, when a method is [B]void[/B] it cannot return a value. There for, the multiply method would have to be like this:
int product;

public void multiply(int firstVar, int SecondVar){

See the difference? To return a value, you had to manipulate a global variable instead. Your method obviously did not need to return a value; what good does returning "0" do? (If you need true or false, make it a boolean method, and have it return true or false, not "true" or "false" [those are strings]). Therefore, you would waste precious (not really) memory by allocating it; void methods take up less memory (RAM).

[B]Please mark this as solved if I did[/B]