Java.Core.Which Operator Allows You to Forcibly Throw an Exception in Java?

The throw operator is used in Java to forcibly throw an exception.

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1. The throw Operator

✅ Purpose:
The throw keyword is used to manually trigger an exception in Java.

✅ Syntax:

throw new ExceptionType("Error message");

• ExceptionType must be a subclass of Throwable (e.g., Exception, RuntimeException).
• The throw statement must be followed by an exception object.

✅ Example: Throwing an Exception Manually

public class ThrowExample {
    public static void main(String[] args) {
        throw new RuntimeException("This is a forced exception");
    }
}

🛑 Output:

Exception in thread "main" java.lang.RuntimeException: This is a forced exception

2. throw vs. throws

🔹 throw (single exception, inside method)

• Used inside a method to forcefully throw an exception.
• Requires an instance of Throwable (e.g., new Exception("Error")).

🔹 throws (declaration, multiple exceptions)

• Used in method signatures to declare exceptions a method might throw.
• Multiple exceptions can be declared, separated by commas.

✅ Example: throw vs. throws

class Example {
    // Declaring an exception using throws
    public static void riskyMethod() throws IllegalAccessException {
        throw new IllegalAccessException("Access denied!"); // Forcing an exception
    }

    public static void main(String[] args) {
        try {
            riskyMethod();
        } catch (IllegalAccessException e) {
            System.out.println("Caught: " + e.getMessage());
        }
    }
}

3. Using throw with Custom Exceptions

You can create and throw custom exceptions using throw.

✅ Example: Custom Exception with throw

class AgeException extends Exception {
    public AgeException(String message) {
        super(message);
    }
}

public class CustomThrowExample {
    public static void checkAge(int age) throws AgeException {
        if (age < 18) {
            throw new AgeException("Age must be at least 18");
        }
    }

    public static void main(String[] args) {
        try {
            checkAge(16);
        } catch (AgeException e) {
            System.out.println("Caught: " + e.getMessage());
        }
    }
}

🛑 Output:

Caught: Age must be at least 18

Final Thoughts

✔ Use throw to manually trigger exceptions.
✔ Use throws to declare exceptions in method signatures.
✔ Always throw an instance of Throwable or its subclasses.