Why is the variable not being assigned?

Question

Java

I understand that it's a noob question, but I still couldn't figure it out because there's not enough time.
Why when passing a variable in this way, the variable takes the value of Null.
When I output this variable in this class, it outputs Null.
Explain if not difficult.

Answer 1

Probably because you're passing null to the method, aren't you?
Add
System.out.println(LOGIN == null);
to your code.
And read the java code convention, your class, method and variable names are just awful.

Answer 2

And how do you call your USER_NAME_AGREEMENT(String LOGIN) method?
Try running this class:

public class Test{
   public static String userName;

   public static void main(String args[]){
         userNameAgreement("test login");
   }

   public static void userNameAgreement(String login){
        userName = login;
        System.out.println("Agreement: " + userName);
   }
}

Yes, and everything should work for you.
Maybe you are passing null or not calling your USER_NAME_AGREEMENT(String LOGIN) method.
Of course it's up to you how you write your code, but I would join protven . Usually in java, in capital letters, using the example of your public String USER_NAME, they write static variables, etc. and methods are lowercase.

Answer 3

Check for null at the beginning of the method and you will be happy
. There will be something like

public String USER_NAME;
    public void USER_NAME_AGREEMENT(String LOGIN) {
    	if (LOGIN == null) throw new IllegalArgumentException();
    	USER_NAME = LOGIN;
    	System.out.println("Agreement: " + USER_NAME);
    }