To reference the externalized help context IDs, which are defined in a ResourceBundle properties file, UI components must implement an interface class to declare the abstract helpKey constants.
The following example is from the org.eclipse.datatools.connectivity.ui source code.
    package org.eclipse.datatools.connectivity.internal.ui;
    /**
      * helpKey_constants_for_plug-in: org.eclipse.datatools.connectivity.ui
      */
    public interface IHelpConstants {
        /*
         * CONTEXT_ID_CP_PROPERTY_PAGE =
         * Basic profile name/description/auto-connect property page
         */
        public static final String CONTEXT_ID_CP_PROPERTY_PAGE =
            "CONTEXT_ID_CP_PROPERTY_PAGE"; //$NON-NLS-1$
    
        /*
         * CONTEXT_ID_CP_WIZARD_PAGE =
         * wizard selection page in New Connection Profile wizard
         */
        public static final String CONTEXT_ID_CP_WIZARD_PAGE =
            "CONTEXT_ID_CP_WIZARD_PAGE"; //$NON-NLS-1$
    
        /*
         * CONTEXT_ID_INTRO_WIZARD_PAGE =
         * Basic intro page for new connection profile wizard
         */
        public static final String CONTEXT_ID_INTRO_WIZARD_PAGE =
            "CONTEXT_ID_INTRO_WIZARD_PAGE"; //$NON-NLS-1$
    ...
    }
        
    public static final String MY_HELP_KEY = "MY_HELP_KEY";
                    where MY_HELP_KEY is the literal character string used as the helpKey constant
                    in a UI control.