Quick Answer

Handle unimplemented abstract method errors.

Understanding the Issue

Occurs when a class doesn't implement all required abstract methods, typically due to binary incompatibility (changing interfaces without recompiling).

The Problem

This code demonstrates the issue:

Java Error 
interface Shape { void draw(); }
class Circle implements Shape {} // Missing draw()

The Solution

Here's the corrected code:

Java Fixed 
// Solution 1: Implement all abstract methods
class Circle implements Shape {
    @Override
    public void draw() { /* implementation */ }
}

// Solution 2: Recompile all dependencies
// mvn clean install

// Solution 3: Make class abstract
abstract class Circle implements Shape {}

Key Takeaways

Maintain consistent versions between interfaces and implementations.