code: public static boolean hasInterface(Class intf, Class cls) {
      boolean	result;
      String	key;
  
      key = intf.getName() + "-" + cls.getName();
      if (m_CheckInterface.containsKey(key))
        return m_CheckInterface.get(key);
  
      result = intf.isAssignableFrom(cls);
      m_CheckInterface.put(key, result);
  
      return result;
    }
docs: Checks whether the given class implements the given interface.
  
  @param intf      the interface to look for in the given class
  @param cls       the class to check for the interface
  @return          TRUE if the class contains the interface