254. Monitoring garbage collectors

Monitoring the activity and evolution in the timeline of your GC is a major aspect in order to identify potential performance issues. For instance, you may be interested in monitoring pause times, identifying the frequency and types of GC events, what spaces are filled up by the triggered GC events, and so on. The main goal is to collect as much information as possible that can be helpful in troubleshooting performance issues related to heap memory and GC evolution.

Any modern IDE provides profilers that contain (among other related things) information and real-time graphs about the GC epochs/cycles. For instance, the following figure is from the NetBeans IDE, which displays the GC evolution (heap status) as an item of the toolbar (by simply clicking on that area, you can force the GC to perform garbage collection):

Figure 12.22: NetBeans display GC evolution on the toolbar

Of course, a more detailed view is available via the NetBeans...