Java - Exception Class Creation

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Introduction

You can create your own exception classes.

They must extend an existing exception class.

Syntax

The keyword extends is used to extend a class. 

<Class Modifiers> class ClassName extends <<Superclass Name>> {
}

ClassName is your exception class name and <<Superclass Name>>is an existing exception class name.

To create a MyException class, which extends the java.lang.Exception class.

The syntax would be as follows: 

public class MyException extends Exception {
   // Body for MyException class goes here
}

Demo

public class Main {

  public static void main(String[] args) throws Exception {

    try {/*  ww  w.  j  a  v  a  2s.c o  m*/
      throw new MyException("File not found");
    } catch (MyException e) {
      // Code for the catch block goes here
    }
  }
}

class MyException extends Exception {

  public MyException() {
    super();
  }

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

  public MyException(String message, Throwable cause) {
    super(message, cause);
  }

  public MyException(Throwable cause) {
    super(cause);
  }
}

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