Example: Throw new Exception

Here’s a simple example of throwing an exception when a condition is not met:

public class Example {
    public static void checkAge(int age) {
        if (age < 18) {
            throw new IllegalArgumentException("Age must be 18 or older.");
        } else {
            System.out.println("Age is valid.");
        }
    }

    public static void main(String[] args) {
        try {
            checkAge(16); // This will throw an exception
        } catch (IllegalArgumentException e) {
            System.out.println("Caught Exception: " + e.getMessage());
        }
    }
}

Explanation:

  • In the checkAge method, if the age is less than 18, an IllegalArgumentException is thrown with a message.
  • The main method calls checkAge(16), which triggers the exception.
  • The catch block catches this exception and prints the error message.