Quick Answer

Diagnose and fix memory exhaustion.

Understanding the Issue

This error occurs when the JVM cannot allocate more memory, often from memory leaks or insufficient heap space.

The Problem

This code demonstrates the issue:

Java Error 
// Causes memory leak
List<byte[]> list = new ArrayList<>();
while (true) {
    list.add(new byte[1024 * 1024]); // 1MB chunks
}

The Solution

Here's the corrected code:

Java Fixed 
// Solution 1: Increase heap size
// java -Xmx1024m MainClass

// Solution 2: Fix memory leaks
try {
    // process data
} finally {
    resource.close(); // Always release resources
}

// Solution 3: Profile memory usage
// Use VisualVM or JConsole

// Solution 4: Optimize data structures
Map<Key, Value> cache = new WeakHashMap<>(); // Not strong referenced

// Solution 5: Use off-heap memory for large data
// Libraries like ByteBuffer or Chronicle Map

Key Takeaways

Monitor memory usage and optimize data structures.