What does "shutting down application" refer to in the error message logged to the WebLogic log? (4258209)

Our WebLogic server crashed. I see the following message in the WebLogic log:

[12/28/11 21:02:58:586 GMT+08:00] 00000619 PerformaSureA E PerformaSure Agent An unexpected exception occurred, shutting down application. You may want to contact Quest Software customer support if you see this error again: java.lang.OutOfMemoryError

I have the following questions:

Question 1). What does "shutting down application" refer to in the error message? Is it just referring to the Foglight JavaEE agent?

Question 2). What are the circumstances when java.lang.OutOfMemoryError errors can be reported?