Solved

new keyword in numberFormat class

Posted on 2016-08-09
7
35 Views
Last Modified: 2016-09-13
package com.example.java;

import java.text.NumberFormat;

public class Main {

    public static void main(String[] args) {
	int R = 42;
    String fromR = Integer.toString(R);
    System.out.println(R);

    boolean Rb = true;
        Boolean.toString(Rb);
        System.out.println(Rb);


        long Rl = 100_000;
        //Long.toString(Rl);
        NumberFormat formatt = NumberFormat.getNumberInstance();
        String formatted = formatt.format(Rl);
        //with commas instead of underscore
        System.out.println(formatted);

    }
}

Open in new window




numberformatting

is this an existing class

why do I not need a NEW keyword

numberFormat object=new numberFormat()
0
Comment
Question by:rgb192
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
7 Comments
 
LVL 14

Accepted Solution

by:
CPColin earned 200 total points (awarded by participants)
ID: 41749499
NumberFormat is an abstract class, so you can't instantiate it using the new operator.
1
 
LVL 35

Assisted Solution

by:mccarl
mccarl earned 200 total points (awarded by participants)
ID: 41749670
And just to expand a little more on the above, the method "getNumberInstance" is a static method of the class. This means that it is a method of the class and not an object, and so you don't NEED an object to call that method. The "new" keyword creates an object of a class, but since you don't need the object, you don't need to use "new".
1
 
LVL 5

Assisted Solution

by:Jan Louwerens
Jan Louwerens earned 100 total points (awarded by participants)
ID: 41753199
getNumberInstance() is what's called a Factory Method. If you'd like to know more information about how these work, there is a ton of information about this design pattern on the web.
0
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 35

Expert Comment

by:mccarl
ID: 41771111
@rgb192,

Do you have any further questions on this subject, or are you happy with the above comments?
0
 

Author Comment

by:rgb192
ID: 41792990
so it is static and what is class under it in the factory
0
 
LVL 5

Expert Comment

by:Jan Louwerens
ID: 41794490
The exact implementation class is unknown. It's only known that it implements the NumberFormat interface (which is what you should be programming to, anyway).
0

Featured Post

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

INTRODUCTION Working with files is a moderately common task in Java.  For most projects hard coding the file names, using parameters in configuration files, or using command-line arguments is sufficient.   However, when your application has vi…
Java contains several comparison operators (e.g., <, <=, >, >=, ==, !=) that allow you to compare primitive values. However, these operators cannot be used to compare the contents of objects. Interface Comparable is used to allow objects of a cl…
Video by: Michael
Viewers learn about how to reduce the potential repetitiveness of coding in main by developing methods to perform specific tasks for their program. Additionally, objects are introduced for the purpose of learning how to call methods in Java. Define …
Viewers will learn about basic arrays, how to declare them, and how to use them. Introduction and definition: Declare an array and cover the syntax of declaring them: Initialize every index in the created array: Example/Features of a basic arr…

749 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question