Concurrent Modification Exception? So I'm writing a program for my cse115 class (quite literaly, it has to do something with graphics, we get to decide what we're doing), and i'm running into an error i have no idea how I'm getting. The error is, as the title suggests, a Concurrent Modification Exception, and I'm programming in java. I'm pretty sure its from this one 2-d array that i have filled up with a type of graphic, but i'm not sure what's actualy wrong with it. What I'm doing with the array is just filling it up in a nested for loop, and then displaying the values on the screen. I'll post the code later (not currently at the lab where i have the code stored).