How to call a method of another class ?

Question

Hello,
I�d like to know how to call a method of another class. I have to classes (class 1 and class 2), class 1 instantiates an object of class 2 and executes the rest of the method. Later, class 1 has to call a method of class 2, sending a message to do something in the object... Does anybody know how to do that ? Do I have to use interface ? Could you please help me ?
Thanks.
Bruno.

Answer 1

Hi Schiller,
The codes are the following:
COMECO
import javax.swing.UIManager;
import java.awt.*;
import java.net.*;
import java.io.*;
import java.awt.event.*;
import javax.swing.*;
//Main method
class comeco {
public static void main(String[] args) {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
catch(Exception e) {
AGORA testeagora=new AGORA();
// Code for socket
int port;
     ServerSocket server_socket;
     BufferedReader input;
     try {
     port = Integer.parseInt(args[0]);
     catch (Exception e) {
     System.out.println("comeco ---> port = 1500 (default)");
     port = 1500;
     try {
     server_socket = new ServerSocket(port);
     System.out.println("comeco ---> Server waiting for client on port " +
               server_socket.getLocalPort());
     // server infinite loop
     while(true) {
          Socket socket = server_socket.accept();
          System.out.println("comeco ---> New connection accepted " +
                    socket.getInetAddress() +
                    ":" + socket.getPort());
          input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
          // print received data
          try {
          while(true) {
               String message = input.readLine();
               if (message==null) break;
               System.out.println("comeco ---> " + message);
testeagora.teste(message);
          catch (IOException e) {
          System.out.println(e);
          // connection closed by client
          try {
          socket.close();
          System.out.println("Connection closed by client");
          catch (IOException e) {
          System.out.println(e);
     catch (IOException e) {
     System.out.println(e);
AGORA
import javax.swing.UIManager;
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.io.*;
import javax.swing.*;
import java.net.*;
//public class AGORA {
public class AGORA {
boolean packFrame = false;
//Construct the application
public AGORA() {
try {
Main frame = new Main();
System.out.println("agora ---> Criou o frame");
//Validate frames that have preset sizes
//Pack frames that have useful preferred size info, e.g. from their layout
if (packFrame)
frame.pack();
else
frame.validate();
//Center the window
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
Dimension frameSize = frame.getSize();
if (frameSize.height > screenSize.height)
frameSize.height = screenSize.height;
if (frameSize.width > screenSize.width)
frameSize.width = screenSize.width;
frame.setLocation((screenSize.width - frameSize.width) / 2, (screenSize.height - frameSize.height) / 2);
frame.setVisible(true);
catch(Exception e)
{ System.out.println("agora ---> " +e);
// Tem que criar a THREAD e ver se funciona
public void remontar (final String msg) {
try {
               System.out.println("agora ---> Passou pelo Runnable");
System.out.println("agora --> Mensagem que veio do comeco para agora: "+ msg);
Main.acao(msg);
catch(Exception x) {
x.printStackTrace();
MAIN
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import com.borland.jbcl.layout.*;
import javax.swing.border.*;
import java.net.*;
import java.io.*;
public class Main extends JFrame {
// ALL THE CODE OF THE INTERFACE
//Construct the frame
public Main() {
enableEvents(AWTEvent.WINDOW_EVENT_MASK);
try {
jbInit();
catch(Exception e) {
e.printStackTrace();
public void acao() {
// C�digo para mudar a interface
Runnable setTextRun=new Runnable() {
public void run() {
try {
               System.out.println("main ---> Passou pelo Runnable");
TStatus.setText("main ---> Funcionou");
catch(Exception x) {
x.printStackTrace();
System.out.println("main ---> About to invokelater");
SwingUtilities.invokeLater(setTextRun);
System.out.println("main ---> Back from invokelater");
// Aqui vai entrar o m�todo para ouvir as portas sockets.
// Ele deve ouvir e caso haja alguma nova mensagem, trat�-la para
// alterar as vari�veis e redesenhar os pain�is
// Al�m disso, o bot�o de refresh deve aparecer ativo em vermelho
//Component initialization
private void jbInit() throws Exception {
// Initialize the interface
//Setting | Host action performed
public void SetHost_actionPerformed(ActionEvent e) {
     int port;
     ServerSocket server_socket;
     BufferedReader input;
System.out.println("main ---> port = 1500 (default)");
     port = 1500;
     try {
     server_socket = new ServerSocket(port);
     System.out.println("main ---> Server waiting for client on port " +
               server_socket.getLocalPort());
     // server infinite loop
while(true) {
          Socket socket = server_socket.accept();
          System.out.println("main ---> New connection accepted " +
                    socket.getInetAddress() +
                    ":" + socket.getPort());
          input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String espaco=new String(": ");
     JLabel teste2=new JLabel(new ImageIcon("host.gif"));
          PHost.add(teste2);
System.out.println("main ---> Adicionou host na interface");
          repaint();
System.out.println("main ---> Redesenhou a interface");
          setVisible(true);
          // print received data
          try {
          while(true) {
               String message = input.readLine();
               if (message==null) break;
               System.out.println("main ---> " + message);
          catch (IOException e2) {
          System.out.println(e2);
          // connection closed by client
          try {
          socket.close();
          System.out.println("main ---> Connection closed by client");
          catch (IOException e3) {
          System.out.println(e3);
     catch (IOException e1) {
     System.out.println(e1);
public void OutHost_actionPerformed(ActionEvent e) {
          repaint();
          setVisible(true);
//Help | About action performed
public void helpAbout_actionPerformed(ActionEvent e) {
Main_AboutBox dlg = new Main_AboutBox(this);
Dimension dlgSize = dlg.getPreferredSize();
Dimension frmSize = getSize();
Point loc = getLocation();
dlg.setLocation((frmSize.width - dlgSize.width) / 2 + loc.x, (frmSize.height - dlgSize.height) / 2 + loc.y);
dlg.setModal(true);
dlg.show();
//Overridden so we can exit on System Close
protected void processWindowEvent(WindowEvent e) {
super.processWindowEvent(e);
if(e.getID() == WindowEvent.WINDOW_CLOSING) {
fileExit_actionPerformed(null);
public void result(final String msg) {
// C�digo para mudar a interface
Runnable setTextRun=new Runnable() {
public void run() {
try {
               System.out.println("main ---> Chamou o m�todo result para mudar a interface");
System.out.println("main --> Mensagem que veio do agora para main: "+ msg);
TStatus.setText(msg);
catch(Exception x) {
x.printStackTrace();
System.out.println("main --> About to invokelater");
SwingUtilities.invokeLater(setTextRun);
System.out.println("main --> Back from invokelater");
[]�s.