JBoss.org Community Documentation

10.1. Memory and Thread Monitoring

The jboss.system:type=ServerInfo MBean provides several attributes that can be used to monitor the thread and memory usage in a JBoss instance. These attributes can be monitored in many ways: through the JMX Console, from a third-party JMX management tool, from shell scripts using the twiddle command, etc... The most interesting attributes are shown below.


This is the current free memory available in the JVM.


This is the number of active threads in the JVM.


This is the number of active thread groups in the JVM.

These are useful metrics for monitoring and alerting, but developers and administrators need a little more insight than this. The Java 5 JVMs from Sun provide more detailed information about the current state of the JVM. Some of these details are exposed by JBoss through operations on the SystemInfo MBean.


This operations shows the size and current usage of all JVM memory pools. This operation is only available when using Java 5.


This operations shows all threads currently running in the JVM. When using Java 5, JBoss will display a complete stack trace for each thread, showing you exactly what code each thread is executing.


This operations shows all threads currently running in the JVM along with the total CPU time each thread has used. The operation is only available in Java 5.