ensure QueryExplorer.getInstance() is only used inside display thread or checked for null

[abelhegedus]

The Query Explorer code is full of lines similar to the following:

QueryExplorer.getInstance().someMethod()

As the getInstance() contains access to the workbench, it only returns a non-null value if invoked from a display thread, so anytime the code is invoked from a non-display thread, it will throw an NPE.

Possible solutions:

• make sure getInstance() is called only inside the display thread
• make sure that the result of getInstance() is always checked for nullness before invoking anything on it.

[abelhegedus]

Thanks for going through the occurences, I'm closing the ticket. Anybody with additional requests can reopen it on will.