CODEWITHSUNDEEP
java
Dondaj
Dondaj

Reputation: 35

Prevent variable from being assigned twice

I have a question, I am creating a class, and in my class, i have some variables that i want just to be assigned once, but i would like multiple instances of the class. Example:

public class UserHandler{

private ArrayList<String> users = new ArrayList<String>();

public void addUser(String user) {
users.add(user)
}

}

This is just some example code. Would the ArrayList be instantiated multiple times, or just once, if i create multiple instances of the class?

Upvotes: 0

Views: 505

Answers (1)

Davide Lorenzo MARINO
Davide Lorenzo MARINO

Reputation: 26926

If the array is declared as

private ArrayList<String> users = new ArrayList<String>();

it will be created once for each instance of UserHandler.

If you change the declaration to static 

private static ArrayList<String> users = new ArrayList<String>();

it will be created only once and shared between different instances.

You can find more about class members (static keyword) here on the tutorial of Oracle:

static keyword to create fields and methods that belong to the class, rather than to an instance of the class.

Upvotes: 2

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