Exception Handling: Robust Error Management

Enterprise software must handle errors gracefully. Java's exception hierarchy helps distinguish between recoverable and fatal errors.

Checked vs Unchecked Exceptions

• Checked (Exception): Verified at compile-time. The developer must handle it or declare it (e.g., IOException).
• Unchecked (RuntimeException): Not verified at compile-time. Usually indicates programming errors (e.g., NullPointerException, IndexOutOfBoundsException).

The try-with-resources Statement

Modern Java ensures resources like database connections or file streams are closed automatically.

java code
try (BufferedReader br = new BufferedReader(new FileReader(path))) {
    return br.readLine();
} catch (IOException e) {
    logger.error("Failed to read file", e);
}

Creating Custom Exceptions

In business logic, use custom exceptions to provide context.

java code
public class InsufficientFundsException extends Exception {
    public InsufficientFundsException(String message) {
        super(message);
    }
}

The "Anti-Patterns" to Avoid

1. Swallowing Exceptions: catch(Exception e) {} — This makes debugging impossible.
2. Catching Throwable: Never catch Throwable as it includes Error (like OutOfMemoryError) which you shouldn't handle.
3. Using Exceptions for Flow Control: Only use exceptions for exceptional conditions, not for standard conditional logic.