The dummy operator Read Database (replacing jdbc_connectors:read_database) cannot be executed.

I creat a process and run it in the RM Studio, it shows correct result in Results panel. Then I want to use it in my program, so I create a test class to run the process by using code like this:

But result isn't what I expected. 

Then I debug it and find the reason, "myProcess" created by "processXML" isn't right, but "processXML" is right.

Process myProcess = new Process(processXML);
myProcess.setProcessLocation(new RepositoryProcessLocation(pLoc));

But why? What is a dummy operator? 

Does anybody know the answer? Thanks a lot.