• August 29, 2014
  • Core Java
  • Comments Off on Finally in java

Finally in java

finally:

finally block is mainly used to do clean-up task. It is always executed even when no exception occur. It will not execute only in case program exits using System.exit() or because of some fatal error cause program to abort. It is followed by either catch or try block.

Note: A try block can have one or more catch block associated with it, but only one finally block can be associates with it. 

Syntax of finally without catch:

try{

      //block of statements

}finally{

}

Syntax of finally with catch:

try{

      //block of statements

}catch(){

}finally{

}

Example: finally block when exception occur and handled.

FinallyExceptionExample2.java

/**
 * This program used to show the use of finally block 
 * when exception occur and handled.
 * @author javawithease
 */
class ArithmaticTest{
	/**
	 * This method is used to divide two integers.
	 * @param num1
	 * @param num2
	 * @author javawithease
	 */
	public void division(int num1, int num2){
		try{
			//java.lang.ArithmeticException here.
			System.out.println(num1/num2);
                //catch ArithmeticException here.
		}catch(ArithmeticException e){
			//print exception.
			System.out.println(e);
		}finally{//It will always execute.
		      System.out.println("Finally will always execute.");
		}
 
	   System.out.println("Remaining code after exception handling.");
	}
}
 
public class FinallyExceptionExample2 {
	public static void main(String args[]){
		//creating ArithmaticTest object
		ArithmaticTest obj =  new ArithmaticTest();
 
		//method call
		obj.division(20, 0);
	}
}

Output:

java.lang.ArithmeticException: / by zero
Finally will always execute.
Remaining code after exception handling.

Download this example.

Example: finally block when exception occur but not handled.

FinallyExceptionExample3.java

/**
 * This program used to show the use of finally block 
 * when exception occur but not handled.
 * @author javawithease
 */
class ArithmaticTest{
	/**
	 * This method is used to divide two integers.
	 * @param num1
	 * @param num2
	 * @author javawithease
	 */
	public void division(int num1, int num2){
		try{
			//java.lang.ArithmeticException here.
			System.out.println(num1/num2);
		}finally{//It will always execute.
		      System.out.println("Finally will always execute.");
		}
 
	  System.out.println("Remaining code after exception handling.");
	}
}
 
public class FinallyExceptionExample3 {
	public static void main(String args[]){
		//creating ArithmaticTest object
		ArithmaticTest obj =  new ArithmaticTest();
 
		//method call
		obj.division(20, 0);
	}
}

Output:

Finally will always execute.
Exception in thread "main" 
java.lang.ArithmeticException: / by zero
at com.javawithease.business.ArithmaticTest.division
(FinallyExceptionExample3.java:17)
at com.javawithease.business.FinallyExceptionExample3.main
(FinallyExceptionExample3.java:32)

Download this example.

Example: finally block when no exception occur.

FinallyExceptionExample1.java

/**
 * This program used to show the use of finally block 
 * when no exception occur.
 * @author javawithease
 */
class ArithmaticTest{
	/**
	 * This method is used to divide two integers.
	 * @param num1
	 * @param num2
	 * @author javawithease
	 */
	public void division(int num1, int num2){
		try{
			//java.lang.ArithmeticException here.
			System.out.println(num1/num2);
                //catch ArithmeticException here.
		}catch(ArithmeticException e){
			//print exception.
			System.out.println(e);
		}finally{//It will always execute.
		       System.out.println("Finally will always execute.");
		}
 
	   System.out.println("Remaining code after exception handling.");
	}
}
 
public class FinallyExceptionExample1 {
	public static void main(String args[]){
		//creating ArithmaticTest object
		ArithmaticTest obj =  new ArithmaticTest();
 
		//method call
		obj.division(20, 10);
	}
}

Output:

2
Finally will always execute.
Remaining code after exception handling.

Download this example.
 
Next Topic: throw in java with example.
Previous Topic: Nested try block in java with example.

Related Topics:

Some important terms for Exception Handling.
Exception handling in java.
try and catch blocks in java with example.
Multiple catch blocks in java with example.
Nested try block in java with example.
Finally in java with example.
throw in java with example.
throws in java with example.
Exception propagation in java with example.
Exception handling with method overriding in java.
Custom exception in java with example.
Commonly used exception methods of Throwable class in java.

 


Comments are closed.