Invoke method in another source file?

Question

Hello,
I'm new to java programming (and OO in general), I feel that I have a basic understanding of OO design (just to give an idea of where I'm at).
My problem: I can't figure out how to access methods or instance variables in other source files (.java files) within the same package. Here's a couple examples of what I'm trying to do....
ex1.
MainFrame.java
public class MainFrame extends JFrame {
MainFrame mainFrame = new MainFrame();
mainFrame.setVisible(true);
~I have a button on this form that when clicked does this....
MainFrame.this.setVisible(false); *as a side note, I don't understand  exactly what this statement means, but it's the only way I could make it hide the frame (so feel free to help me on this too if you don't mind-the confusion is; to hide a label I can just say mylablename.setVisible(false) why do I have to say myframename.this.setVisible when I'm dealing with a Frame?)
NewEstimate estimate = new NewEstimate(); //inst. and show next frame
estimate.setVisible(true);
~NewEstimate is the name of the other java source file (NewEstimate.java)
so after clicking the button my new form loads, and I have another button that when clicked should close my estimate form and show mainFrame again, this is where my problem is....
I want to just dipose this form because I want it instaniated each time so I just want to dispose() this one so...
MainFrame.setVisible(true); //show the main frame again
dispose();
....I get the error MainFrame symbol not found and I have tried all kinds of ways like mypackagename.MainFrame.setVisible(true);
mainFrame.setVisible.setVisible(true);
MainFrame.mainFrame.setVisible(true);
all to no avail thus leading me to believe that one of those is correct but my problem is something else...
I also have the same problem when trying to invoke a method in another source file and the same when trying to evaluate a variable...
if in source1.java I have somewhre String name = mike;
then in source2.jave I have if name equals mike do something, I get the same errors; symbol cannot be resolved.
Thanks for taking the time to help.
Mike

Answer 1

Thanks for your reply. Here is a test case that resembles what I'm trying to do. Note that I don't want to dipose of Frame1, (my reason is that I only want to initialize it 1 time (when the program is started), so I only want to hide it when it calls Frame2. Then when the user clicks the button on Frame2, dispose of Frame2 and show Frame1 again. The specific error I'm getting in Frame2.java is in the line frame1.setVisible(true) and is frame1 symbol cannot be resolved. That is my MAIN problem (main priority at this point) but I am also having a problem evaluating or referncing variables in Frame1.java from Frame2.java; I'm assuming though that the problems are related.
Frame1.java
package thepackage;
import javax.swing.JPanel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.*;
public class Frame1 extends JFrame {
     private JPanel jContentPane = null;
     private JButton jButton = null;
     public String name = "Bill"; //This is the variable I need to evaluate in
frame2
     public Frame1() {
          super();
          initialize();
     private void initialize() {
          this.setSize(new java.awt.Dimension(300,200));
          this.setSize(300, 200);
          this.setContentPane(getJContentPane());
          this.setTitle("Frame1");
     public static void main(String[] args) {
          Frame1 frame1 = new Frame1();
          frame1.setVisible(true);
     private JPanel getJContentPane() {
          if (jContentPane == null) {
               jContentPane = new JPanel();
               jContentPane.setLayout(null);
               jContentPane.add(getJButton(), null);
          return jContentPane;
     private JButton getJButton() {
          if (jButton == null) {
               jButton = new JButton();
               jButton.setBounds(new java.awt.Rectangle(58,132,182,26));
               jButton.addActionListener(new java.awt.event.ActionListener() {
                    public void actionPerformed(java.awt.event.ActionEvent e) {
                         Frame1.this.setVisible(false);
                         Frame2 frame2 = new Frame2();
                         frame2.setVisible(true);
          return jButton;
Frame2.java
package thepackage;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JLabel;
public class Frame2 extends JFrame {
     private JPanel jContentPane = null;
     private JButton jButton = null;
     private JLabel jLabel = null;
     public Frame2() {
          super();
          initialize();
showFrame(); //set the label text to the string in variable "name"
     private void initialize() {
          this.setSize(300, 200);
          this.setContentPane(getJContentPane());
          this.setTitle("Frame2");
     private JPanel getJContentPane() {
          if (jContentPane == null) {
               jLabel = new JLabel();
               jLabel.setBounds(new java.awt.Rectangle(53,40,131,16));
               jLabel.setText("");
               jContentPane = new JPanel();
               jContentPane.setLayout(null);
               jContentPane.add(getJButton(), null);
               jContentPane.add(jLabel, null);
          return jContentPane;
     private JButton getJButton() {
          if (jButton == null) {
               jButton = new JButton();
               jButton.setBounds(new java.awt.Rectangle(49,117,136,35));
               jButton.addActionListener(new java.awt.event.ActionListener() {
                    public void actionPerformed(java.awt.event.ActionEvent e) {
                         frame1.setVisible(true);
                         dispose();
          return jButton;
     private void showName(){
          jLabel.setText(name); -> gives error Component.name is not
visible
}