jconsole - Monitoring JVM

jconsole is a GUI tool provided with JDK. One can use it just by typing jconsole in command prompt like javac, java, etc. Its GUI is simple and gets updated at a regular interval.



It automatically detects the jvms running on the machine and lists to select. It also provides an interface for connecting to remote processes.

Suppose you select a JVM running on a local machine means it will list certain details of that JVM.

The default overview page lists Heap memory useage, Threads, Classes and CPU usage all updating at a regular interval. The Memory tab can be used to force garbage collection on that particular JVM. There is a Perform GC button in that tab and by clicking on it you can see a sudden decrease in memory chart mostly.

Also the Threads tab will be useful in multithreaded environment to see the number of active threads.

Java provides JMX (Java Management Extensions) to write our own monitors of JVMs.