How to give a variable value through another method in another class in Java

Question

Simply put here is what I am trying to do:

class Main { 
    public static void main (String[] args) {
        List option = new List();
        SetGet call = new SetGet();
        option.names();
        call.getName();
    }
}

class List {
    public void names() {
        SetGet tell = new SetGet();
        tell.setName("Frank");
    }
}

class SetGet() {
    private String info;

    String getName() {
        return info;
    }

    public void setName(String name) {
        info = name;
    }
}

Essentially I have a main method that will tell another method from another class to set the name of something. Yet whenever I request getName from the main method, it always comes back null even though I already set a name for it. This is a really simplified version of what I am trying to do. Any assistance is greatly appreciated.

You are creating two separate instances of SetGet (using new SetGet()). And the names() method creates an instance, sets the name, but then discards the newly created instance, because you don't return it or store it in a field. — MC Emperor
– MC Emperor, Commented Jan 9, 2022 at 15:03
Thanks for the quick reply. I am new to programming, how would I call the value of a variable set by another method from a different class? — evogamer
– evogamer, Commented Jan 9, 2022 at 15:07

Abdullah Mohammad Motiullah · Accepted Answer · 2022-01-09 15:04:46Z

1

When you call option.names(); in your main method, it creates a new SetGet object named tell and sets its name to "Frank".

After that you call call.getName(); on a newly created SetGet named call.

Both the SetGet objects are not related, they are different.

answered Jan 9, 2022 at 15:04

Abdullah Mohammad Motiullah

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Comments

Moritz Hartmann · Accepted Answer · 2022-01-09 15:13:44Z

0

You creating 2 different objects of SetGet. You can try to return the object tell and overwrite call with the returned object.

class Main {
  public static void main (String[] args) {
    List option = new List();
    SetGet call =  new SetGet();
    call = option.names();
    System.out.println(call.getName());
  }
}

class List {
  public SetGet names() {
    SetGet tell = new SetGet();
    tell.setName("Frank");
    return tell;
  }
}

class SetGet {
  private String info;

  String getName() {
    return info;
  }

  public void setName(String name) {
    info = name;
  }
}

edited Jan 9, 2022 at 15:13

answered Jan 9, 2022 at 15:08

Moritz Hartmann

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2 Comments

evogamer Over a year ago

But what if under the class List, I tell the method SetGet() to set other variables like tell.setAge and tell.setYearBorn, would the return tell be able to return all those values for me? If you can point to me what to research, that would be greatly appreciated. Just trying to learn as much as I can.

Moritz Hartmann Over a year ago

First of all SetGet is a class not a method. The object tell in list is a local object just for the method names. if you want more methods overwriting the same object you should create tell as a local object of List, then if you add more methods to List the returned tell would always have the same properties for the object of List(in this case call). For better understanding try to search for object oriented programming.

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