How To Make Paint Program Not Error Out

I am screwing around with mouse listeners so i decided to make a basic paint program. It works fine but when it draws more than 100 circles it errors out. i know why its doing it (its because i set the array to 100) but my question is how to make it so it has not limit in the array.

Here is the code

public class PaintProject extends Applet {
int numClicks = 100;
int numCicles;
int xCoord[];
int yCoord[];
boolean paint;

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