try catch finally in java

try block:

• The functionality of try keyword is to identify an exception object.
• And catch that exception object and transfer the control along with the identified exception object to the catch block by suspending the execution of the try block.
• All the statements which are proven to generate exceptions should be place in try block.

Syntax of try block:

try
{
//try block
//keep those statements which may
//throw run time exceptions
}

catch Block:

•  The functionality of catch block is to receive the exception class object that has been send by the "try".
• And catch that exception class object and assigns that exception class object to the reference of the corresponding exception class defined in the catch block.
• And handle the exception that has been identified by "try".
• "try"  block identifies an exception and catch block handles the identified exception.

Syntax:

catch(Exception e)
{
//catch block.
//one argument of type java.lang.Exception
//catches the exceptions thrown by try block
}

finally block:

• finally blocks are the blocks which are going to get executed compulsorily irrespective of exceptions.
• finally blocks are optional blocks.

Syntax:

finally
{
//This is the finally block.
}

Example Program:

1. package com.instanceofjava;
2. public class MyException {
3.  
4.  public static void main(String a[]){
5.  
6.   try{         
7. int i = 10/0;             
8.   System.out.println("This statement won't executed");      
9.  } 
10. catch(Exception ex){
11.  
12.   System.out.println("This block is executed immediately after an exception is thrown");
13.  
14.   }
15.  finally{
16. System.out.println("This block is always executed");}
17.  }
18.  
19. }

Output:

1. This block is executed immediately after an exception is thrown
2. This block is always executed.