code: public static Bus getDefaultBus(ClassLoader contextClassLoader)
     {
        ClassLoader origClassLoader = SecurityActions.getContextClassLoader();
        try
        {
           SecurityActions.setContextClassLoader(contextClassLoader);
           return BusFactory.getDefaultBus();
        }
        finally
        {
           SecurityActions.setContextClassLoader(origClassLoader);
        }
     }
docs: Gets (and internally sets) the default bus after having set the thread
  context class loader to the provided one (which affects the Bus
  construction if it's not been created yet). The former thread context
  class loader is restored before returning to the caller.
  
  @param contextClassLoader
  @return the default bus