Here are three ways: (1) using the Greenfoot class method getRandomNumber; (2) using the java.lang.Math class random method; or, (3) creating and using a java.util.Random object Examples of each creating integer values, 0 <= x < 600, follows: In example (3), you probably will never find the Random object created in the same line as shown. You will normally see the Random object created separately and assigned to a object reference variable to be used multiple times, as below:

Not the best way, but a simple and easy way to it if you're a beginner : for example, you could do this in your World class : (if you have a 300 by 200 map) it will spawn some coins that I named "coin0", "coin1" etc in a random location between 0 and 300 on x axis, and 0 and 200 on y axis.