code: public Object removeAttribute(String key) {
  
          if (m_attributeMap != null) {
              return m_attributeMap.remove(key);
          }
          return null;
      }
docs: Removes an attribute from the request context.<p>
  
  @param key the name of the attribute to remove
  
  @return the removed attribute, or <code>null</code> if no attribute was set with this name