Introduction

Java JVM becomes unresponsive when garbage collection pause exceeds timeout threshold. This guide provides step-by-step diagnosis and resolution with specific commands and code examples.

Symptoms

Typical symptoms and error messages when this issue occurs:

bash
GC pause time exceeds threshold: 15234ms
Application is unresponsive during garbage collection
GC overhead limit exceeded

Observable indicators: - Application logs show errors or exceptions - JVM crashes or becomes unresponsive - Related services may fail or timeout

Common Causes

  1. 1.Deadlock and hang issues are caused by:
  2. 2.Circular dependencies in lock acquisition
  3. 3.Missing timeout in wait operations
  4. 4.Incorrect thread synchronization
  5. 5.Resource starvation

Step-by-Step Fix

Step 1: Check Current State

bash
java -version

Step 2: Identify Root Cause

bash
jcmd <pid> VM.info

Step 3: Apply Primary Fix

java
// Primary fix: update configuration
@Configuration
public class AppConfig {
    @Bean
    public MyBean myBean() {
        MyBean bean = new MyBean();
        bean.setTimeout(30000);
        return bean;
    }
}

Apply this configuration and restart the application.

Step 4: Apply Alternative Fix (If Needed)

java
// Alternative fix: use properties
# application.properties
app.timeout=30000
app.retry-count=3
app.enabled=true

Monitor JVM metrics after changes using JConsole or VisualVM.

Step 5: Verify the Fix

After applying the fix, verify with:

bash
jcmd <pid> VM.info && jstat -gc <pid> 1s 5

Expected output should show successful operation without errors.

Common Pitfalls

  • Setting Xms larger than Xmx
  • Ignoring JVM crash logs
  • Not tuning GC for workload type

Best Practices

  • Use G1GC for heaps > 4GB
  • Set Xms equal to Xmx for production
  • Monitor GC logs continuously
  • Java OutOfMemoryError Heap Space
  • Java GC Overhead Limit Exceeded
  • Java JVM Crash Signal Error