The only conditions required are:
 1) Play a video using a webview ( e.g. youtube)
 2) Use Engine.load(url) to browse to other websites
 3) The crash will inevitably occur after some time..may take a few minutes of browsing

I managed to reproduce the crash every single time with about 150 different code tweaks in the last 5 days.

The system crashes immediately if you use a for loop to bulk load other URLs. (so that you can crash it faster).

The crash report is the following:

A fatal error has been detected by the Java Runtime Environment:
#
# EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x00000000673028e0, pid=3544, tid=7532
#
# JRE version: Java(TM) SE Runtime Environment (7.0_40-b26) (build 1.7.0_40-ea-b26)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (24.0-b45 mixed mode windows-amd64 compressed oops)
# Problematic frame:
# C [glass.dll+0x128e0]