i18n-swing

i18n-swing provides drop-in replacements for every standard Swing component. Each Resourceful* class extends its standard Swing counterpart and automatically re-applies all localizable properties on the Event Dispatch Thread when the application locale changes.

Artifact: dev.javai18n:i18n-swing · Requires: Java 17+ · View Javadoc →

<dependency>
    <groupId>dev.javai18n</groupId>
    <artifactId>i18n-swing</artifactId>
    <version>1.2.2</version>
</dependency>

module my.module {
    requires dev.javai18n.swing;
}

Quick start

1. Extend a Localizable container

public class MyFrame extends LocalizableJFrame {
    static {
        MyModuleRegistrar.ensureRegistered();
    }

    @Override
    public Locale[] getAvailableLocales() {
        return new Locale[]{ Locale.ROOT, Locale.FRANCE };
    }
}

2. Define a resource bundle

MyFrameBundle.json:

{
    "okButton": {
        "type": "dev.javai18n.swing.AbstractButtonPropertyBundle",
        "Text": "OK",
        "Mnemonic": 79
    }
}

MyFrameBundle_fr.json:

{
    "okButton": {
        "type": "dev.javai18n.swing.AbstractButtonPropertyBundle",
        "Text": "D'accord",
        "Mnemonic": 68
    }
}

3. Create Resourceful components

MyFrame frame = MyFrame.create();
Resource okResource = new Resource(frame, "okButton");
ResourcefulJButton okButton = ResourcefulJButton.create(okResource);

// Switch the entire UI to French — every attached component updates on the EDT
frame.setBundleLocale(Locale.FRANCE);

Localizable containers

These classes serve as the locale-event source for all Resourceful components they own.

Class	Extends	Notes
`LocalizableJFrame`	`JFrame`	Standard application frame; bundle key `"windowProperties"` uses `FramePropertyBundle`
`LocalizableJDialog`	`JDialog`	Modal or non-modal dialog; bundle key `"windowProperties"` uses `FramePropertyBundle`
`LocalizableJWindow`	`JWindow`	Undecorated window; bundle key `"windowProperties"` uses `WindowPropertyBundle`

Resourceful components

The base set of localized properties for every Resourceful component is: name, tooltip, font, accessible name, accessible description (from JComponentPropertyBundle).

Buttons and toggles

Class	Extends	Additional localized properties
`ResourcefulJButton`	`JButton`	text, label, mnemonic, 7 icon types
`ResourcefulJCheckBox`	`JCheckBox`	text, label, mnemonic, 7 icon types
`ResourcefulJRadioButton`	`JRadioButton`	text, label, mnemonic, 7 icon types
`ResourcefulJToggleButton`	`JToggleButton`	text, label, mnemonic, 7 icon types

Menus

Class	Extends	Additional localized properties
`ResourcefulJMenu`	`JMenu`	text, label, mnemonic, 7 icon types
`ResourcefulJMenuBar`	`JMenuBar`	—
`ResourcefulJMenuItem`	`JMenuItem`	text, label, mnemonic, 7 icon types
`ResourcefulJCheckBoxMenuItem`	`JCheckBoxMenuItem`	text, label, mnemonic, 7 icon types
`ResourcefulJRadioButtonMenuItem`	`JRadioButtonMenuItem`	text, label, mnemonic, 7 icon types
`ResourcefulJPopupMenu`	`JPopupMenu`	—
`ResourcefulJPopupMenuSeparator`	`JPopupMenu.Separator`	—

Text components

Class	Extends
`ResourcefulJTextField`	`JTextField`
`ResourcefulJTextArea`	`JTextArea`
`ResourcefulJEditorPane`	`JEditorPane`
`ResourcefulJTextPane`	`JTextPane`
`ResourcefulJPasswordField`	`JPasswordField`
`ResourcefulJFormattedTextField`	`JFormattedTextField`

Data and selection

Class	Extends	Additional localized properties
`ResourcefulJComboBox`	`JComboBox`	item values (string array)
`ResourcefulJList`	`JList`	—
`ResourcefulJSpinner`	`JSpinner`	—
`ResourcefulJSlider`	`JSlider`	—
`ResourcefulJTree`	`JTree`	—
`ResourcefulJTable`	`JTable`	—
`ResourcefulJTableHeader`	`JTableHeader`	—
`ResourcefulJProgressBar`	`JProgressBar`	progress string
`ResourcefulJScrollBar`	`JScrollBar`	—
`ResourcefulJColorChooser`	`JColorChooser`	—
`ResourcefulJFileChooser`	`JFileChooser`	dialog title, approve button text/tooltip

Panes and containers

Class	Extends	Additional localized properties
`ResourcefulJPanel`	`JPanel`	—
`ResourcefulJScrollPane`	`JScrollPane`	—
`ResourcefulJSplitPane`	`JSplitPane`	—
`ResourcefulJTabbedPane`	`JTabbedPane`	per-tab title, tooltip, icon
`ResourcefulJInternalFrame`	`JInternalFrame`	title, frame icon
`ResourcefulJLayeredPane`	`JLayeredPane`	—
`ResourcefulJDesktopPane`	`JDesktopPane`	—
`ResourcefulJDesktopIcon`	`JDesktopIcon`	—
`ResourcefulJRootPane`	`JRootPane`	—
`ResourcefulJViewport`	`JViewport`	—
`ResourcefulJOptionPane`	`JOptionPane`	dialog title, button option labels

Layout helpers

Class	Extends	Additional localized properties
`ResourcefulBox`	`Box`	—
`ResourcefulBoxFiller`	`Box.Filler`	—
`ResourcefulJLabel`	`JLabel`	text, mnemonic, icon, disabled icon
`ResourcefulJSeparator`	`JSeparator`	—
`ResourcefulJToolBar`	`JToolBar`	—
`ResourcefulJToolBarSeparator`	`JToolBar.Separator`	—
`ResourcefulJToolTip`	`JToolTip`	tip text

Spinner editors

Class	Extends
`ResourcefulJSpinnerDefaultEditor`	`JSpinner.DefaultEditor`
`ResourcefulJSpinnerDateEditor`	`JSpinner.DateEditor`
`ResourcefulJSpinnerNumberEditor`	`JSpinner.NumberEditor`
`ResourcefulJSpinnerListEditor`	`JSpinner.ListEditor`

Utility menu items

Class	Extends	Description
`LocaleJMenuItem`	`ResourcefulJRadioButtonMenuItem`	Displays a locale name; sets the application locale when selected; shows a radio-button check mark for the active locale
`LookAndFeelJMenuItem`	`ResourcefulJMenuItem`	Displays a Look and Feel name; applies it when selected

Property bundles

Bundle	Extends	Fields
`ComponentPropertyBundle`	—	name, font, accessible name, accessible description
`JComponentPropertyBundle`	`ComponentPropertyBundle`	+ tooltip
`AbstractButtonPropertyBundle`	`JComponentPropertyBundle`	+ text, label, mnemonic, icon, pressed, selected, disabled, disabled-selected, rollover, rollover-selected icons
`JLabelPropertyBundle`	`JComponentPropertyBundle`	+ text, mnemonic, icon, disabled icon
`JComboBoxPropertyBundle`	`JComponentPropertyBundle`	+ values (string array)
`JProgressBarPropertyBundle`	`JComponentPropertyBundle`	+ progress string
`JInternalFramePropertyBundle`	`JComponentPropertyBundle`	+ title, frame icon
`JTabbedPaneTabPropertyBundle`	—	tab title, tab tooltip, tab icon (one entry per tab)
`JOptionPanePropertyBundle`	`JComponentPropertyBundle`	+ title, options (string array)
`JFileChooserPropertyBundle`	`JComponentPropertyBundle`	+ dialog title, approve button text/tooltip
`JToolTipPropertyBundle`	`JComponentPropertyBundle`	+ tip text
`WindowPropertyBundle`	`ComponentPropertyBundle`	+ icon images (list)
`FramePropertyBundle`	`WindowPropertyBundle`	+ title

Testing notes

LocalizationDelegate initializes its locale from Locale.getDefault() at construction time. Maven Surefire’s -Duser.language flag does not change Locale.getDefault() in the forked JVM — it is propagated via System.setProperty() after the JVM’s default locale has already been set.

Rule: In any test that asserts specific string values from a bundle, always pin the locale explicitly before constructing the Localizable object:

TestComponentSource source = TestComponentSource.create();
// create() calls setBundleLocale(Locale.ROOT) immediately after construction

ResourceBundle rb = ResourceBundle.getBundle(
    "com.example.MyFrameBundle", Locale.ROOT); // always pass explicit locale

See the full guide for the complete explanation.

i18n-core Foundation library

i18n-fx JavaFX bindings