Add below parameter to vm arguments of JVM.
-XX:+HeapDumpOnOutOfMemoryError
This writes heap dump on OutOfMemoryError to your eclipse directory.
Say for example, if your working eclipse directly is "D:\Work\eclipse", there can find hprof extension file. It looks like below.
ex: java_pid1864.hprof
1864 represents running javaw process id.
It would be useful to analyze the cause using using memory profiler tools ex: Eclipse MAT, JProfiler and YourKit
