Did you want to put a condition on populating the world? or are you just trying to learn how to create a loop using the 'while' keyword? I ask because you need a boolean argument (whether a value or expression) to be used with the 'while' keyword. with the 'condition' returning a boolean value and the 'execute this' being populating the world. The loop will repeat as long as 'condition' returns a 'true' value. That is, unless you 'break' from the loop from within (which should also be conditional).

Java has a trail (tutorial) called Language Basics that you maybe should take a look at.

i just want to know how to add to 10 worms, 5 crabs, and 2 Lobsters using the populateWorld method... this is what i have but it dose absolutely nothing public void populateWorld() { int k=0; while(k<5) { addObject(new Crab(), Greenfoot.getRandomNumber(560), Greenfoot.getRandomNumber(560)); } int i=0; while(i<2) { addObject(new Lobster(), Greenfoot.getRandomNumber(560), Greenfoot.getRandomNumber(560)); } int j=0; while (j<10) { addObject(new Worm(), Greenfoot.getRandomNumber(560), Greenfoot.getRandomNumber(560)); } }

Try 'while ((k++)<5)' and similar for 'i' and 'j'. Unless the value of the boolean turns 'false' at some point, your scenario will appear to freeze (loop infinitely).