JAVA : EXCEPTION : HIERARCHY

JAVA : EXCEPTION : HIERARCHY

why cant we use  new Exception(myMsg) instead of new MyException(myMsg) .....?

We can handle different exception separately like

catch(MyException e) { //do some operation ..}

catch(Exception e) { //do some other operaton...}


Custom Exception Class:

Example1: With out super(str2)

class MyException extends Exception{
   String str1;

   MyException(String str2) {
 str1=str2;   //Note: not calling super(str2)
   }
   public String toString(){ 
 return ("MyException Occurred: "+str1) ;
   }
}

class Example1{
   public static void main(String args[]){ //Note: throws is not require, bez JVM will take care
 try{
  System.out.println("Starting of try block");
  // I'm throwing the custom exception using throw
  throw new MyException("This is My error Message");
 }
 catch(MyException exp){
  System.out.println("Catch Block") ;
  System.out.println(exp) ; //prints .toString()
 }
   }
}

O/P

Starting of try block
Catch Block
MyException Occurred: This is My error Message

Example2: With  super(str)

class InvalidProductException extends Exception
{
    public InvalidProductException(String s)
    {
        // Call constructor of parent Exception
        super(s); //Using super
    }
}
 
public class Example1
{
   void productCheck(int weight) throws InvalidProductException{  //Note : throws is require bez its our custom method and it is checked exception
 if(weight<100){
  throw new InvalidProductException("Product Invalid");
 }
   }
   
    public static void main(String args[])
    {
     Example1 obj = new Example1();
        try
        {
            obj.productCheck(60);
        }
        catch (InvalidProductException ex)
        {
            System.out.println("Caught the exception");
            System.out.println(ex.getMessage());
        }
    }
}

O/P

Caught the exception
Product Invalid