You mention you have 6 GB, do you know how much of this you have allocated to Geneious?
You should be able to see in the memory usage bar in the bottom left. Under the Sources panel. If you're running in the development environment then you can change this by editing the JVM options to have a higher Xmx value.
It's hard to tell what has happened from just the crash.log. I can see the UI thread is busy drawing a hierarchy of components, that might be related. But it may be unrelated. Did you receive an error dialog with the option to send in a report to us prior to the one shown in your screenshot? If you were able to send that in then that would help diagnose the issue.