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Java Java Objects Harnessing the Power of Objects Constants

I'm still having trouble understandig the static keyword, what difference does it make to a variable?

I'm still having trouble understandig the static keyword, what difference does it make to a varible? how does it differ from a non-static variable?

3 Answers

Hi Kristoffer,

This is a tricky concept to get your head round, I agree!

The static keyword, when used on a member variable is associated with the class not the objects/instances of the class. So, you can use it when no objects exist.

public class Steve{
  public static String name = "Steve";

Here's a class definition. In your code you can access this variable:

// somehwere in your code

You call it off the class name, hence the capitalized Steve.

The variable is common across all instances too. So, you can do this:

public class Steve{
  public static String name = "Steve";
  public static int howMany = 0;

  public Steve(){
    // I'm a constructor

So, here in the constructor, we increment the howMany variable. This will count how many instances of Steve exist (one's enough, trust me!). This means every instance of Steve will contain the same value in howMany So:

Steve oneSteve = new Steve();
Steve twoSteve = new Steve();
Steve threeSteve = new Steve();

Every instance here will have the value 3 held in howMany. oneSteve.howMany and threeSteve.howMany will both hold 3. This means you can count instances of your class, or how many times the constructor has run, anyway.

I hope that helps!


Oziel Perez
Oziel Perez
61,321 Points

To further elaborate on the answer, Say you have oneSteve.property = true, and twoSteve.property = false. Those two variable exist in different parts of memory because they are part of two separate objects. However, "static" means that there is only one reference of the variable, in this case 'howMany'. So calling oneSteve.HowMany, twoSteve.howMany, or access it off the class as Steve.howMany, it will be the same variable store in the same memory reference, which is why you can access this variable without instantiating a class as an object.

Good input. :+1: :+1: :+1:

good answer thanks!


Halisson Alves
Halisson Alves
14,149 Points

Thanks a lot Steve Hunter ... Now it's very clear for me with your explanation!

No problem, Halisson - glad to help. :+1:


Thanks! :+1:

Anil kumar N
Anil kumar N
658 Points

i cleared my doubt too. Now, thats called a real team :)