👀 Views: 0 💬 Answers: 1 📅 Created: 2025-06-12

eclipse java design-patterns debugging Java

I'm dealing with I'm dealing with I've searched everywhere and can't find a clear answer. I'm stuck on something that should probably be simple. I'm currently working on an application utilizing the Abstract Factory design pattern, but I'm running into a `NullPointerException` when trying to instantiate my product objects. My setup includes Eclipse IDE 2023-09, and I'm using Java 17. The relevant code snippets are as follows: ```java public interface ProductA { void doSomething(); } public class ProductA1 implements ProductA { public void doSomething() { System.out.println("ProductA1 doing something"); } } public class ProductA2 implements ProductA { public void doSomething() { System.out.println("ProductA2 doing something"); } } public interface AbstractFactory { ProductA createProductA(); } public class Factory1 implements AbstractFactory { public ProductA createProductA() { return new ProductA1(); } } public class Factory2 implements AbstractFactory { public ProductA createProductA() { return new ProductA2(); } } public class Provider { public static AbstractFactory getFactory(String choice) { if (choice.equalsIgnoreCase("Factory1")) { return new Factory1(); } else if (choice.equalsIgnoreCase("Factory2")) { return new Factory2(); } return null; } } public class Client { public static void main(String[] args) { AbstractFactory factory = Provider.getFactory("Factory1"); ProductA product = factory.createProductA(); product.doSomething(); // This line throws NullPointerException } } ``` I've checked the return values from `Provider.getFactory()` and confirmed that it returns a non-null factory instance. However, when I call `createProductA()`, it seems to return null, leading to the `NullPointerException` when I attempt to call `doSomething()`. I even added debug statements to track down what’s being returned, and it appears that the factory's `createProductA()` method is executed but doesn’t return a valid product object. I've tried cleaning and rebuilding the project in Eclipse, as well as invalidating the Eclipse cache, but nothing seems to have resolved the scenario. Additionally, I ensured that there are no circular dependencies that could cause this behavior. Anyone encountered a similar question or have insights into what might be going wrong? Has anyone else encountered this? My development environment is Windows. What's the best practice here? I'd be grateful for any help.