What
- JBoss instance accepts no more new requests.
- Processing in-flight request becomes very slow or timed out.
Why
Wrong design or implementation of customer's application / third party library or framework
- Infinite loop
- Too long SQL / WS out-band calls
- Thread deadlock
Wrong estimation of thread tuning
- All available threads are busy and JBoss runs out of resources to execute new request
- Too long request processing
- Waiting for response from peer(e.g. RDBMS)
- Contention of resources
- Underestimation of peak load
- Too long JVM Full GC
Java VM or JBoss bug
How
- Get the Thread dump
- Get the GC log