Starting with release 5.0, Java SE provides a comprehensive solution for monitoring and managing your applications, as well as for monitoring and managing the Java Virtual Machine.
Monitoring and Management Documentation: J2SE 5.0 | Java SE 6
Java Management Extensions(JMX) Documentation: J2SE 5.0 | Java SE 6
The JMX Home Page
Monitoring and Management Forums
Monitoring and Managing Java SE 6 Platform Applications