You are showing this: which is the 'jre' (java runtime environment)-- and is not the 'jdk' (java development kit). You need to download the 'jdk' (which probably has a 'jre' included with it).

excuse me danpost, but im new on greenfoot. is it possible if you take a look at my scenario and tell me the code i need for a scroll world. ive tried taking a look at others but i dont really understand how to make it suitable to my world. if u can it would be much appreciated!

I cannot look at a scenario that is not available to look at. Also, you need to be more specific as to what type of scrolling world you are wanting (what directtions scrolling is allowed, what will cause the scrolling -- automatic or player-induced -- and what limits are imposed on the scrolling).

i would like to scroll from left to right, similar to the mario concept. So i would have platoforms to walk on throught the scroll as well to land on.I would like the scroll to be 'player' induced and all i want the length to be accustomed to about 3 or more platforms long. p.s if u have time to help me the landing on a platform thing( it is not consistent and my player somtimes falls through), it would be much appreciated!

I have a Jump and Run Demo w/Moving Platform scenario; you can look at the code to see how I do it. As far as scrolling, my Bee Quick (ImgScroll Demo) scenario scrolling class will probably work.

The ImgScroll class you are using should not need any modifications. If you do not want to scroll vertically, then use '0' (zero) for amount to scroll in that direction scroll(dx, 0);