Accessing variable from method class to use in GUI class

I am writing a code to add 2 numbers from two textfield and having the sum show up in a third textfield. Howerver, when I set the third textfield to display value Z, which is the sum, I get the error "cannot find symbol". What am I doing wrong?

import javax.swing.*;  
import java.awt.event.*;  
public class A implements ActionListener{     
    JTextField tf1,tf2,tf3;  
    JButton b1;   
    A(){  
        JFrame f= new JFrame(); 
        JLabel myLabel= new JLabel("Enter First Value");
        myLabel.setBounds(50,50,150,20); 
        tf1=new JTextField();  
        tf1.setBounds(50,75,250,20);
        JLabel mysecondLabel= new JLabel("Enter Second Value");
        mysecondLabel.setBounds(50,125,150,20);  
        tf2=new JTextField();  
        tf2.setBounds(50,150,250,20);  
        tf3=new JTextField();  
        tf3.setBounds(160,225,140,20);  
        tf3.setEditable(false);   
        b1=new JButton("Sum");  
        b1.setBounds(50,225,95,20);
        b1.addActionListener(this); 

        f.add(tf1);f.add(myLabel);f.add(tf2);f.add(mysecondLabel);f.add(tf3);f.add(b1);  
        f.setSize(300,300);  
        f.setLayout(null);  
        f.setVisible(true);  
    }         

        public void actionPerformed(ActionEvent e) {  
        String s1=tf1.getText();  
        String s2=tf2.getText();
    if(e.getSource()!=b1){  
        return;  
    }
    
    int x = Integer.parseInt(s1);
    int y = Integer.parseInt(s2);
            
    String result = B.Z;

    tf3.setText(result); 
}  public static void main(String[] args) {  
    new A(); 
}
}

import javax.swing.*;  
import java.awt.event.*;
public class B {
    public static int myMethod(int x, int y) {
      int Z;
      Z = x + y;
      return Z;
      }
}

Your B class doesn't have a static field called Z that you can access by calling B.Z. You are not calling myMethod(x, y);. Try String result = String.valueOf(B.myMethod(x, y)); and see if that works.