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Finally Block In Java

Finally Block
 
In Java, finally block is used to perform important code such as closing connection, stream etc.
 
Finally block is mainly used in Java. It always execute whether an exception is handled or not. It must be followed by try or catch block.
 
Let’s understand with the flowchart, given below.

13
 
Why we use Java finally?

Finally block allows us to run any cleanup-type statements, which we want to execute, no matter what happens in the protected code such as closing a file, closing connection etc.
 
Usage of finally block

Let's see an example, given below, where an exception doesn't occur.
 
Code
  1. package exceptionHandling;  
  2. public class FinallyExample1 {  
  3.     public static void main(String args[]) {  
  4.         try {  
  5.             int num = 36 / 6;  
  6.             System.out.println(num);  
  7.         } catch (NullPointerException e) {  
  8.             System.out.println(e);  
  9.         } finally {  
  10.             System.out.println("finally block....");  
  11.         }  
  12.         System.out.println("Rest code...");  
  13.     }  
  14. }  
14

Output

15

Let's see an example, given below, where an exception occurs and not handled.
 
Code
  1. package exceptionHandling;  
  2. public class FinallyExample2 {  
  3.     public static void main(String args[]) {  
  4.         try {  
  5.             int num = 36 / 0;  
  6.             System.out.println(num);  
  7.         } catch (NullPointerException e) {  
  8.             System.out.println(e);  
  9.         } finally {  
  10.             System.out.println("finally block....");  
  11.         }  
  12.         System.out.println("Rest code...");  
  13.     }  
  14. }  
16

Output

17

Let's see an example, given below, where an exception occurs and handles.
 
Code
  1. package exceptionHandling;  
  2. public class FinallyExample3 {  
  3.     public static void main(String args[]) {  
  4.         try {  
  5.             int num = 36 / 0;  
  6.             System.out.println(num);  
  7.         } catch (ArithmeticException e) {  
  8.             System.out.println(e);  
  9.         } finally {  
  10.             System.out.println("finally block....");  
  11.         }  
  12.         System.out.println("rest code...");  
  13.     }  
  14. }  
18

Output

19

When we don't handle the exception before terminating the program, JVM executes finally block automatically.
 
Each try block can be zero or more catch blocks, but only one finally block and the finally block does not execute if the program exits.
 
Summary

Thus, we learnt that finally block is used to perform an important code and also learnt why we need to use it in Java.