One event can generate multiple dumps. The agents that produce each dump run sequentially and their order is determined by the priority keyword set for each agent.
Examination of the output from -Xdump:what shows that a gpf event produces a snap trace, a Javadump, and a system dump. In this example, the system dump will run first (priority 999), the snap dump second (priority 500), and the Javadump last (priority 10):
–Xdump:heap:events=vmstop,priority=123
The maximum value allowed for priority is 999. Higher priority dump agents will be started first.
If you do not specifically set a priority, default values are taken based on the dump type. The default priority and the other default values for a particular type of dump, can be displayed by using -Xdump:<type>:defaults. For example:
java -Xgcpolicy:metronome -Xdump:heap:defaults -version Default -Xdump:heap settings: events=gpf+user filter= file=/home/user/heapdump.%Y%m%d.%H%M%S.%pid.phd range=1..0 priority=40 request=exclusive+prepwalk opts=PHD