Hello, everyone!
Before I get to the issue I would like to say that this is my first time posting here, and that the question required to register was quite clever

. That is all.
Now, the issue... The Display.getAvailableDisplayModes() hangs for several seconds. I measured the time it takes for it to return (multiple times) and the average time I got was about 8.2 seconds!

But I found the reason why it does that! Multiple monitors plugged in! Unplugging my second display reduced the time to aprox. 0.45 seconds, so that's a temporary fix until this gets fixed (if it can be fixed).
The difference between the number of display modes possibly has something to do with it. 284 with both displays on, 62 without the other display.
-I have a BenQ monitor and a Samsung TV
-AMD Radeon HD 6870 2xCrossfire
-Display drivers are up to date (13.11 beta v9.2, I believe)
-AMD Phenom II X6 1055T
-Windows 7 64-bit
I would also like to mention that one (older, 12.xx) driver version reduced the return time to about 4 seconds, IIRC...
Crossfire didn't have any effect on the length of time the method takes and neither did the OS display settings (show desktop, what is primary display, mirror or expand).
EDIT: Changed subject to show that the issue has been resolved by Spasi.