code: public void setDefaultWorkManager(WorkManager wm)
     {
        if (trace)
           log.tracef("Default WorkManager: %s", wm);
  
        String currentName = null;
  
        if (defaultWorkManager != null)
           currentName = defaultWorkManager.getName();
  
        defaultWorkManager = wm;
  
        if (wm != null)
        {
           workmanagers.put(wm.getName(), wm);
        }
        else if (currentName != null)
        {
           workmanagers.remove(currentName);
        }
     }
docs: Set the default work manager
  @param wm The work manager