Infinite Loop in REST API

Infinite Loop in REST API

Problem: The following code is making an infinite loop when calling /products/{id}. Why?

@RestController
@RequestMapping("/products")
public class ProductController {

    @GetMapping("/{id}")
    public Product getProduct(@PathVariable Long id) {
        return getProduct(id);
    }
}

        

The issue in the Infinite Loop in REST API question is that the method is calling itself recursively without a base case, causing a StackOverflowError due to infinite recursion.

Problematic Code:

@GetMapping("/{id}")
public Product getProduct(@PathVariable Long id) {
    return getProduct(id); // Recursive call without exit condition
}

        

Fix:

Instead of recursively calling getProduct(id), the method should fetch the product from a service or repository.

@Autowired
private ProductService productService;

@GetMapping("/{id}")
public Product getProduct(@PathVariable Long id) {
    return productService.getProductById(id);
}

        

And the ProductService should look something like this:

@Service
public class ProductService {
    public Product getProductById(Long id) {
        // Fetch product from database or mock data
        return new Product(id, "Sample Product");
    }
}     

Key Takeaways:

1. Key Takeaways:
2. Recursive calls without an exit condition cause infinite loops and StackOverflowErrors.
3. Always ensure REST controllers delegate logic to a service instead of self-calling methods.
4. Base cases are required for recursion to terminate correctly.