Java Optional

Many a programmer has been bitten by NullPointerException. While occurring less in Java than C or C++, it may still occur. Now, Java has the idea of an Optional field. An Optional field may or may not contain a value. You can test whether there is a value present or not rather than the awkward null tests that exist.

We can run through several aspects of Optional by using the following code snippet:

import java.util.Optional; 
public class MyOptional { 
    public static void main() { 
        MyOptional program = new MyOptional(); 
        Integer value1 = null; 
        Integer value2 = 123; 
         
        //.ofNullable allows null 
        Optional<Integer> a = Optional.ofNullable(value1); 
         
        //.of does not allow null 
        Optional<Integer> b = Optional.of(value2); 
        System.out.println(program.sum(a,b)); 
    } 
     
    public Integer sum(Optional<Integer> first, Optional<Integer>
      second) { 
        System.out.println...