Quick Answer

Resolve class loading failures at runtime.

Understanding the Issue

This error occurs when a class was present at compile time but not available at runtime, often due to missing dependencies or incorrect classpath.

The Problem

This code demonstrates the issue:

Java Error 
// Class existed during compilation
MyClass obj = new MyClass(); // Fails at runtime

The Solution

Here's the corrected code:

Java Fixed 
// Solution 1: Check runtime classpath
// java -cp "lib/*:." MainClass

// Solution 2: Verify dependencies
// Maven: mvn dependency:tree
// Gradle: gradle dependencies

// Solution 3: Check packaging
// Ensure JAR/WAR contains all required classes

// Solution 4: Check for static initializer errors
// NoClassDefFoundError can mask ExceptionInInitializerError

Key Takeaways

Verify runtime classpath matches compile dependencies.