Caught exception giving me a headache

so i tried to write a DisplayMode to a file, that didn't work out because DisplayMode isn't serializable, So i thought i got rid of that code. Yet i guess that somewhere i missed a line. because i get this line when i try to run my game



java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: org.lwjgl.opengl.DisplayMode



the problem is that i don't know where that is coming from, any ideas on how to find it?

if you are using elipse, you can put a watch on the exception

I found out where the problem was but still, How can i put a watch on the exception using eclipse?