JMX, Scenarios, Business Value, ROI, Monitoring JMX, scenario, business value, ROI, use case 6. How do I detect thread deadlocks automatically? - ThreadMXBean.findDeadlockedThreads() API automatically detects Java thread deadlocks (two or more threads blocked forever, waiting on each other's locks). JMX Gateway polls this MBean every interv

6. How do I detect thread deadlocks automatically?

ThreadMXBean.findDeadlockedThreads() API automatically detects Java thread deadlocks (two or more threads blocked forever, waiting on each other's locks). JMX Gateway polls this MBean every interval, alerts if deadlock detected.

Example deadlock scenario:

• Thread-1 holds Lock-A, waits for Lock-B
• Thread-2 holds Lock-B, waits for Lock-A
• Both threads blocked forever (deadlock)

Nodinite detection:

1. Gateway polls ThreadMXBean.findDeadlockedThreads() every 60 seconds
2. If deadlock detected, Gateway returns: deadlockedThreads: ["Thread-1", "Thread-2"], stackTraces: [...]
3. Nodinite Agent evaluates response, triggers Error alert immediately (deadlock is critical, always Error threshold)
4. Alert includes: Deadlocked thread names, stack traces showing locked objects, timestamp when detected

Alert example:

JVM: Spring Boot Payment Service
Severity: ERROR
Message: Thread deadlock detected - 2 threads deadlocked

Thread-1 (BLOCKED):
  at com.acme.PaymentService.processPayment(PaymentService.java:45)
  - waiting to lock <0x00007f8a4c3d1234> (Database Connection)
  - locked <0x00007f8a4c3d5678> (Payment Queue)

Thread-2 (BLOCKED):
  at com.acme.DatabasePool.getConnection(DatabasePool.java:78)
  - waiting to lock <0x00007f8a4c3d5678> (Payment Queue)
  - locked <0x00007f8a4c3d1234> (Database Connection)

Resolution: Restart JVM immediately (deadlock cannot be resolved automatically, threads stuck forever). Investigate code to fix lock ordering (always acquire Lock-A before Lock-B, never reverse order).