code: protected String invoke(Method doitMethod) throws Exception {
          Object res = doitMethod.invoke(null, new Object[0]);
          return valueString(res);
      }
docs: Invoke the specified "doit-method", a static method with no parameters.
  The {@link DirectExecutionControl#invoke(java.lang.String, java.lang.String) }
  in this class will call this to invoke.
  
  @param doitMethod the Method to invoke
  @return the value or null
  @throws Exception any exceptions thrown by
  {@link java.lang.reflect.Method#invoke(Object, Object...) }
  or any {@link ExecutionControl.ExecutionControlException}
  to pass-through.