How to contribute a new menu to the workbench ?

Eclipse exposed a mechansim to contribute a new menu through "org.eclipse.ui.menus" extension and locationURI.
Requried extension: org.eclipse.ui.menus
LocationURI:  menu:org.eclipse.ui.main.menu

Example:
Below example will contribute a new "Cloud" menu to the eclipse workbench, and this will contain a "Upload" menu item.

 <extension
         point="org.eclipse.ui.menus">
      <menuContribution
            allPopups="false"
            locationURI="menu:org.eclipse.ui.main.menu">
         <menu
               id="com.kk.menus.cloud"
               label="Cloud">
             <command
                  commandId="com.kk.command.upload"
                  style="push">
            </command>
          </menu>
      </menuContribution>
</extension>

Command contribution to upload action:

<extension
         point="org.eclipse.ui.commands">
  <command
            id="com.kk.command.upload"
            name="Upload">
      </command>
</extension>

Handler contribution to upload action:

  <extension
         point="org.eclipse.ui.handlers">
      <handler
            class="com.kk.menus.handlers.UploadHandler"
            commandId="com.kk.command.upload">
      </handler>
   </extension>