Java finally block exception handling

Java finally block is a block used to execute important code such as closing the connection, etc. Java finally block is always executed whether an exception is handled or not. Therefore, it contains all the necessary statements that need to be printed regardless of whether the exception occurs or not.

Few Important points regarding finally block

1. A finally block must be associated with a try block, you cannot use finally without a try block. You should place those statements in this block that must be executed always.

2. Finally block is optional, as we have seen in previous tutorials that a try-catch block is sufficient for exception handling, however, if you place a finally block then it will always run after the execution of the try block.

3. In normal cases when there is no exception in the try block then the finally block is executed after the try block. However, if an exception occurs then the catch block is executed before finally block.

4. An exception in the finally block, behaves exactly like any other exception.

Syntax of Finally block

try {
  //Statements that may cause an exception
}
catch {
 //Handling exception

}
finally {
  //Statements to be executed
}

Example Case 1: When exception does not occur.

Java

package com.prac;

public class FinallyBlockCase1 {
    public static void main(String args[]) {
        try {
            int data = 25 / 5;
            System.out.println(data);
        } catch (Exception e) {
            System.out.println(e);
        } finally {
            System.out.println("finally block 
                                        is always executed");
        }
    }
}

Output

5
finally block is always executed

Example Case 2: When an exception occurs and is caught by the catch block.

Java

package com.prac;

public class FinallyBlockCase2 {
    public static void main(String args[]) {
        try {
            int data = 25 / 0;
            System.out.println(data);
        } catch (ArithmeticException e) {
            System.out.println(e);
        } finally {
            System.out.println("finally block 
                              is always executed");
        }
    }
}

Output

java.lang.ArithmeticException: / by zero
finally block is always executed

Example Case 3: When an exception occurs and is not caught by the catch block.

Java

package com.prac;

public class FinallyBlockCase3 {
    public static void main(String args[]) {
        try {
            int data = 25 / 0;
            System.out.println(data);
        } catch (NullPointerException e) {
            System.out.println(e);
        } finally {
            System.out.println("finally block 
                              is always executed");
        }
    }
}

Output

finally block is always executed
Exception in thread "main" java.lang.ArithmeticException: / by zero
	at com.prac.FinallyBlockCase3.main(FinallyBlockCase3.java:6)

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