class MyException extends Exception {
    /**
     * Default serial ID
     */
    private static final long serialVersionUID = 1L;

    public MyException(String s) {
        super(s);
    }
}

public class CustomExceptionDemo {
    public static void main(String args[]) {
        try {
            throw new MyException("I am a custom exception");
        } catch (MyException ex) {
            System.out.println("Caught");
            System.out.println(ex.getMessage());
        }
    }
}