src/main/java/de/unixwork/im/Main.java

package de.unixwork.im;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.jivesoftware.smack.ConnectionConfiguration;
import org.jivesoftware.smack.tcp.XMPPTCPConnectionConfiguration;
import org.jxmpp.stringprep.XmppStringprepException;


public class Main {

    public static void main(String[] args) {
        // Create the dialog
        JDialog loginDialog = new JDialog((Frame) null, "Login", true);
        loginDialog.setSize(300, 200);
        loginDialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
        loginDialog.setLayout(new BorderLayout(5, 5));

        // Create components
        JPanel inputPanel = new JPanel(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.fill = GridBagConstraints.HORIZONTAL;
        gbc.insets = new Insets(5, 5, 5, 5);

        JLabel usernameLabel = new JLabel("Username:");
        JTextField usernameField = new JTextField(15);
        JLabel domainLabel = new JLabel("Domain:");
        JTextField domainField = new JTextField(15);
        JLabel passwordLabel = new JLabel("Password:");
        JPasswordField passwordField = new JPasswordField(15);

        gbc.gridx = 0;
        gbc.gridy = 0;
        gbc.weightx = 0;
        inputPanel.add(usernameLabel, gbc);

        gbc.gridx = 1;
        gbc.gridy = 0;
        gbc.weightx = 1;
        inputPanel.add(usernameField, gbc);

        gbc.gridx = 0;
        gbc.gridy = 1;
        gbc.weightx = 0;
        inputPanel.add(domainLabel, gbc);

        gbc.gridx = 1;
        gbc.gridy = 1;
        gbc.weightx = 1;
        inputPanel.add(domainField, gbc);

        gbc.gridx = 0;
        gbc.gridy = 2;
        gbc.weightx = 0;
        inputPanel.add(passwordLabel, gbc);

        gbc.gridx = 1;
        gbc.gridy = 2;
        gbc.weightx = 1;
        inputPanel.add(passwordField, gbc);

        JPanel buttonPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT));
        JButton loginButton = new JButton("Login");
        JButton cancelButton = new JButton("Cancel");
        buttonPanel.add(loginButton);
        buttonPanel.add(cancelButton);

        // Add panels to the dialog
        loginDialog.add(inputPanel, BorderLayout.CENTER);
        loginDialog.add(buttonPanel, BorderLayout.SOUTH);

        // Action listeners
        loginButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                String username = usernameField.getText();
                String domain = domainField.getText();
                String password = new String(passwordField.getPassword());
                
                loginDialog.dispose();
                
                try {
                    XMPPTCPConnectionConfiguration config = XMPPTCPConnectionConfiguration.builder()
                            .setUsernameAndPassword(username, password)
                            .setXmppDomain(domain)
                            .setResource("IM5")
                            .setHost(domain)
                            .setPort(5222) 
                            //.addEnabledSaslMechanism("PLAIN")
                            //.setSecurityMode(ConnectionConfiguration.SecurityMode.disabled)
                            .build();
                    
                    Xmpp xmpp = new Xmpp(config);
                    
                    App app = new App(xmpp);
                    
                    xmpp.start();
                } catch (XmppStringprepException ex) {
                    ex.printStackTrace();
                    System.exit(-1);
                } catch (Exception ex) {
                    ex.printStackTrace();
                    System.exit(-1);
                }
            }
        });

        cancelButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                loginDialog.dispose();
            }
        });

        // Center the dialog and make it visible
        loginDialog.setLocationRelativeTo(null);
        loginDialog.setVisible(true);
    }
}