Studying garbage collection

Prerequisites:
Before being able to analyze profiling data to study garbage collection, ensure that the following step has been completed:

Launching or attaching to an application

The Java run-time system performs garbage collection automatically. It finds memory that a program is no longer using and frees it.

In the Profiling Tool, garbage collection can only be run if the process is active. To launch a process, refer to the Launching or attaching to an application topic. Garbage collection is available from Package Statistics view, Class Statistics view as well as the Instance Statistics view when instance level information is collected.

To view details about garbage collection,...

In the Profiling Monitor view, select the monitor or agent.
Right click, then select Open With > Package Statistics. The Package Statistics view opens.
Check that the Live Instances and Collected columns are visible. If they are not, right-click, select Choose Columns., then set these columns to be visible.
View the results in the Packages Statistics view:
- In the Live Instances column, you can see how many instances for the current packages are still alive, and not garbage collected.
- In the Collected column, you can see how many instances for the current packages are garbage collected.
- You can expand the current package to see the same information at the class level or open the Class Statistics view.
- You can also drill down at the instance level using Instance Statistics view if you have collected instance level information in the profiling criteria. To setup the profiling criteria, refer to the Specifying profiling criteria topic.
In the Profiling Monitor view, select the monitor or agent.
Right click and select Run Garbage Collection
In the Package Statistics view, right-click and select Refresh Views. The Package Statistics view is refreshed showing the changes in the number of active instances at the package level.