Weird lagging around in debug mode

Hey there, sep87x ... back again ...

so this isn't really an issue, it's more a question which I am unable to answer. I have the following "problem": after figuring out how this "read-image-files-from-an-external-location-and-bind-it"-thing works, I got to another problem. Usually I work in debug mode so I can edit the code live. At the moment there are only two textures (from that "read-image-files-from-an-external-location-and-bind-it"-thing ... I guess I'll just call it "riffaelabi-thing" in future) being drawn, both of the same size. One of these images changes every five seconds. To prevent the graphics driver from overworking, I register the texture id with the file object in a HashMap object, so LWJGL doesn't need to analyze the image and turn it into its bytes over and over again, and it works sweet, BUT anytime I try to edit the code, Minecraft and the Eclipse IDE slow down for 30 seconds, followed by a sudden termination of the Minecraft window.

My questions are: could it be that this is caused by the debug mode (it works fine on "normal running")? There's no output on the termination. Why?

Thanks in advance

~sep87x