_sqlQueryParamMap = new Vector();
  public ParamInfo( String userDefinedType, String systemType )       throws QueryException   {    _userDefinedType = userDefinedType;    _systemType = systemType;        Class userClass = null;    Class systemClass = null;    try {      systemClass = Class.forName(systemType);    }    catch (Exception e) {      throw new QueryException( "Error: Could not find system defined class: " + systemType );    }    if ( ! userDefinedType.equals("") ) {      try {        userClass = Class.forName(userDefinedType);      }       catch (Exception e) {        throw new QueryException( "The class " + userClass + " could not be found." );      }      if ( ! systemClass.isAssignableFrom(userClass) )        throw new QueryException( "The class " + userDefinedType + " is incompatible with the system defined class " + systemType );      _class = userClass;    }    else      _class = systemClass;  }