code: @Override
      public boolean isValid() {
          if (!_isValid && com.ibm.ejs.ras.TraceComponent.isAnyTracingEnabled() && LoggingUtil.SESSION_LOGGER_CORE.isLoggable(Level.FINE)) {
              //only log this if it is invalid
              String s = _isValid + appNameAndIdString;
              LoggingUtil.SESSION_LOGGER_CORE.logp(Level.FINE, methodClassName, "isValid", s);
          }
          return _isValid;
      }
docs: /*
  @see com.ibm.wsspi.session.ISession#isValid()