code: public void setDetail(String name, Object value) {
          if (value == null) {
              details.remove(name);
          } else {
              details.put(name, value);
          }
          
          if (log.isDebugEnabled()) {
              if (value == null) {
                  log.debug("Detail removed: " + name);
              } else {
                  log.debug("Detail added: " + name + " = " + value);
              }
          }
      }
docs: Sets the specified detail element to the specified value.
  
  @param name Name of the detail element.
  @param value Value for the detail element. A null value removes any existing detail element.