The POST method is used to create resources. As we are creating a department, we use the HTTP POST method. Again, the URI to create a new department in our example is http://www.packtpub.com/resources/departments. The method type for the request is set by the client.

Assume that the Sales department does not exist in our list, and we want to add it to the list. The Sales data representation looks like the following:

{"departmentName":"Sales","manager":"Tony Greig"} 

Now, the sequence diagram of our POST request looks like the following:

The series of steps for the POST request is as follows:

1. A Java client makes a request to the http://www.packtpub.com/resources/departments URI with the HTTP method set to POST.
2. The POST request carries the payload along with it in the form of a JSON representation of the Sales department.
3. The server receives the request and lets the REST framework handle it; our code within the framework executes the proper commands to store the representation, irrespective of which data persistence mechanism is used.
4. Once the new resource is stored, a response code, 2xx (representing successful operation), is sent back. In this example, the server sends 201 Created, which implies that the server has fulfilled the request by creating a new resource. The newly created resource is accessible by traversing the URI given by a Location header field. If it fails, then the server sends the appropriate error code.