setDisplayedMnemonicIndex

The method `setDisplayedMnemonic` is a Java Swing component API function used to associate a mnemonic key with a button or menu item, allowing users to activate the component by pressing a keyboard shortcut. Mnemonics provide an alternative to mouse interactions, enhancing accessibility and usability for keyboard-focused users.

This method is part of the `AbstractButton` class, which includes buttons, checkboxes, and radio buttons, as well as menu items (`JMenuItem`). The function takes a single integer parameter representing the key code of the desired mnemonic character. For example, passing `KeyEvent.VK_S` would assign the 'S' key as the mnemonic for the component.

When enabled, the mnemonic key is displayed with an underscore (e.g., "Save_") in the component’s label. Users can then press `Alt` + the mnemonic key (e.g., `Alt` + `S`) to trigger the component’s action. This feature is particularly useful in forms or dialogs where multiple interactive elements exist, as it reduces reliance on mouse navigation.

The method is distinct from `setMnemonic`, which is part of the `JComponent` class and serves the same purpose but may have slightly different behavior in certain contexts. Developers should ensure that mnemonics are assigned logically to avoid confusion, especially in complex user interfaces.

While useful, mnemonics should be used judiciously, as overuse can clutter interfaces. They are most effective when paired with clear labels and consistent keyboard shortcuts. The `setDisplayedMnemonic` method is particularly valuable in applications targeting accessibility standards, such as those adhering to WCAG guidelines.