Understanding Optional

Optional makes it easier in cases where the result is not really needed. This example can be fine-tuned as needed to explore all of the methods supported.

import java.util.Optional;public class JavaOptional {   public static void main(String args[])   {      JavaOptional javaOptional = new JavaOptional();     final String defaultNum = "25";     //You can pass null when the argument is not provided. Take care of handling it in the next line :)     String firstArg = args.length  0 ? args[0] : null;      Integer firstInt = Integer.parseInt(firstArg);     String secondArg = args.length  1 ? args[1] : defaultNum;      Integer secondInt = Integer.parseInt(secondArg);           //Optional.ofNullable - The parameter passed can be null also.      Optional firstNum = Optional.ofNullable(firstInt);            //Optional.of - a value is must. This will throw NullPointerException is null is passed      Optional secondNum = Optional.of(secondInt);      System.out.println(javaOptional.sum(firstNum,secondNum));   }      public Integer sum(Optional firstNum, Optional secondNum)   {     //isPresent() returns true is the value exists and false otherwise      System.out.println("firstNum.isPresent(): " + firstNum.isPresent());      System.out.println("secondNum.isPresent(): " + secondNum.isPresent());           //orElse() is interesting. If the number is not present orElse executes      Integer firstInt = firstNum.orElse(new Integer(0));            //get() is the other method. Use this only if the value exists or use orElse       Integer secondInt = secondNum.get();        return (firstInt + secondInt);      }}
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