How to set language in text area in Swing?

I need to change the default language into Hebrew in all the text areas in the app. I tried to use Set Local, but it didn't work.

Any idea?

The below code demonstrates the only way I know of to configure a JTextComponent (which JTextArea is a subclass of) so that when it gains input focus it displays Hebrew characters. In other words no need for the user to explicitly change the language after the JTextComponent has gained focus and before the user starts entering text.

import java.awt.BorderLayout;
import java.awt.ComponentOrientation;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.awt.im.InputContext;
import java.util.Locale;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.WindowConstants;

public class DfltHbrw implements ActionListener, FocusListener, Runnable {
    private static final Locale  HEBREW = new Locale("iw", "IL");
    private static final String  EXIT = "\u05E1\u05D2\u05D5\u05E8";

    private JFrame  frame;
    private JTextArea  textArea;

    @Override // java.awt.event.ActionEvent
    public void actionPerformed(ActionEvent event) {
        String actionCommand = event.getActionCommand();
        if (EXIT.equals(actionCommand)) {
            System.exit(0);
        }
    }

    @Override // java.awt.event.FocusListener
    public void focusGained(FocusEvent event) {
        InputContext ic = textArea.getInputContext();
        ic.selectInputMethod(HEBREW);
    }

    @Override // java.awt.event.FocusListener
    public void focusLost(FocusEvent event) {
        // Do nothing.
    }

    @Override // java.lang.Runnable
    public void run() {
        showGui();
    }

    private JPanel createButtons() {
        JPanel buttonsPanel = new JPanel();
        JButton button = new JButton(EXIT);
        button.addActionListener(this);
        buttonsPanel.add(button);
        return buttonsPanel;
    }

    private JScrollPane createTextArea() {
        textArea = new JTextArea(20, 60);
        textArea.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
        textArea.addFocusListener(this);
        JScrollPane scrollPane = new JScrollPane(textArea);
        scrollPane.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
        return scrollPane;
    }

    private void showGui() {
        frame = new JFrame("Hebrew");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.add(createTextArea(), BorderLayout.CENTER);
        frame.add(createButtons(), BorderLayout.PAGE_END);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    /**
     * Start here.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new DfltHbrw());
    }
}

I only added the JButton so that there would be more than one [GUI] component so as to allow transferring focus from one component to another.

The relevant part of the above code is the focusGained() method. I added a focus listener to the JTextArea which calls that method when the JTextArea gains focus. In fact the focusGained() method does the actual work of configuring the JTextArea for displaying Hebrew when the user starts to enter text into it.

Note that the same focusGained() method can be used to configure the JTextArea to display any [supported] language. All you need to change is the Locale argument that is passed to the selectInputMethod() method.

Also note that I only set the ComponentOrientation so that the Hebrew text in the JTextArea would look "natural". It is not required in order to configure the JTextArea for displaying Hebrew.