opensource network monitoring tools developed in java

i want to know the best opensource network monitoring tool developed in java with very good support via forums and which should have the following features ..

• Fault and Alert mgmt
• Performance Poll graphs
• inventory mgmt
• conf开发者_如何学运维ig management

You could try JNM JNM

Check out Hyperic. http://www.hyperic.com/ Sounds like it will fit all your requirements and you can get commercial support should you need or want it.

Try OpenNMS http://www.opennms.org I have been supported by the community very well. Best avenue is IRC.