class MyException extends Exception {
  String msg;
  public MyException(String msg) {
    this.msg = msg;
  }
  public void printMsg() {
    System.out.println("msg = " + msg);
  }
}

// Or you can take a more clever approach, and
// note that string storage and printing is
// built into Exception:
class MyException2 extends Exception {
  public MyException2(String s) {
    //super（S）；
    super(s)；
  }
}

public class E02_ExceptionClass {
  public static void main(String args[]) {
    try {
      throw new MyException(
        "MyException message");
    } catch(MyException e) {
      e.printMsg();
    }
    try {
      throw new MyException2(
        "MyException2 message");
    } catch(MyException2 e) {
      System.out.println(
        "e.getMessage() = " + e.getMessage());
    }
  }
} ///:~