Why ConcurrentModificationException in ArrayList? [duplicate]

Answer 1

You can remove objects from the ArrayList which you are using. I use this in my game engine and it works.

See http://code.google.com/p/game-engine-for-java/source/browse/src/com/gej/map/Map.java#350

for (int i = 0; i < objects.size(); i++) {
    GObject other = objects.get(i);
    if (other.isAlive()) {
        // Update it
    } else {
        // Else remove it
        objects.remove(i);
    }
}

What the error you are having is this does not work for the for each loop. Try in a normal for loop and that should solve your problem.

Change your code to this.

ArrayList list =new ArrayList();
ArrayList remove = new ArrayList();
list.add(100);
list.add(200);
list.add(300);
list.add(400);
// Mark to remove
for (int i=0; i