keyPressEvent.getCharCode() returning 0 for all special keys like enter, tab, escape, etc

the KeyPressHandler is used for example for the SHIFT, CTRL, ALT keys.

If you want to attach an event to another key you have to use KeyDownHandler.

nameField.addKeyDownHandler(new KeyDownHandler() {

    @Override
    public void onKeyDown(KeyDownEvent event) {
        if (event.getNativeKeyCode() == KeyCodes.KEY_ENTER) {
            Window.alert("hello");
        }

    }

});