simple Java program using Swing for GUI and Google Translate API for translation:

 Here is a simple Java program using Swing for GUI and Google Translate API for translation:

```

import javax.swing.*;

import java.awt.*;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.io.BufferedReader;

import java.io.InputStreamReader;

import java.net.HttpURLConnection;

import java.net.URL;

import org.json.JSONObject;

public class Translator extends JFrame {

    private JTextArea textArea;

    private JComboBox<String> languageComboBox;

    private JButton translateButton;

    public Translator() {

        setLayout(new BorderLayout());

        // Text Area

        textArea = new JTextArea(20, 40);

        add(new JScrollPane(textArea), BorderLayout.CENTER);

        // Language Combo Box

        String[] languages = {"English", "Spanish", "French", "German", "Italian", "Portuguese", "Chinese", "Japanese", "Korean"};

        languageComboBox = new JComboBox<>(languages);

        add(languageComboBox, BorderLayout.NORTH);

        // Translate Button

        translateButton = new JButton("Translate");

        translateButton.addActionListener(new ActionListener() {

            @Override

            public void actionPerformed(ActionEvent e) {

                translateText();

            }

        });

        add(translateButton, BorderLayout.SOUTH);

        setSize(600, 400);

        setDefaultCloseOperation(EXIT_ON_CLOSE);

        setVisible(true);

    }

    private void translateText() {

        String text = textArea.getText();

        String language = (String) languageComboBox.getSelectedItem();

        String translatedText = translate(text, language);

        textArea.setText(translatedText);

    }

    private String translate(String text, String language) {

        try {

            URL url = new URL("https://translation.googleapis.com/language/translate/v2?key=YOUR_API_KEY");

            HttpURLConnection connection = (HttpURLConnection) url.openConnection();

            connection.setRequestMethod("POST");

            connection.setRequestProperty("Content-Type", "application/json");

            JSONObject json = new JSONObject();

            json.put("q", text);

            json.put("target", getLanguageCode(language));

            connection.setDoOutput(true);

            connection.getOutputStream().write(json.toString().getBytes());

            int responseCode = connection.getResponseCode();

            if (responseCode == 200) {

                BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));

                String line;

                StringBuilder response = new StringBuilder();

                while ((line = reader.readLine()) != null) {

                    response.append(line);

                }

                reader.close();

                JSONObject jsonResponse = new JSONObject(response.toString());

                return jsonResponse.getJSONArray("data").getJSONObject(0).getString("translations").getJSONObject(0).getString("translatedText");

            } else {

                return "Error: " + responseCode;

            }

        } catch (Exception e) {

            return "Error: " + e.getMessage();

        }

    }

    private String getLanguageCode(String language) {

        switch (language) {

            case "English":

                return "en";

            case "Spanish":

                return "es";

            case "French":

                return "fr";

            case "German":

                return "de";

            case "Italian":

                return "it";

            case "Portuguese":

                return "pt";

            case "Chinese":

                return "zh-CN";

            case "Japanese":

                return "ja";

            case "Korean":

                return "ko";

            default:

                return "en";

        }

    }

    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {

            @Override

            public void run() {

                new Translator();

            }

        });

    }

}

```

Replace `YOUR_API_KEY` with your actual Google Translate API key.

Note:

- This program uses the Google Translate API, which requires a API key.

- The program translates the text in the text area to the selected language.

- The program uses the `getLanguageCode` method to get the language

 code for the selected language.

- The program uses the `translate` method to translate the text using the Google Translate API.