General questions on how to get started with Oracle OEPE and databases

Question

My company has a server in the cloud, written using Ruby on Rails. The server is designed to work with a browser, so it communicates via standard HTTP.
The server has an SQL database.
The server sends and receives HTTP requests from clients, which are then used to either update the database or retrieve information from the database.
The database can be edited from a separate admin dashboard.
I have recently rewritten our client software as a native android app. The new app makes calls to the server that look like browser calls. I have used Eclipse to develop the Android app.
Sounds pretty standard so far, right? :-)
I now want to replace the Ruby on Rails server with a new Java server that I will write. I want to use Eclipse to develop the new server. During development, I want to be able to have the new Android app communicate with the development server software that will reside on my desktop.
So I was thinking that Oracle's tools might be perfect for me, if only I knew which tools to use. There are lot to choose from. :-)
I believe that all I need is OEPE and a database. I would like to keep it pretty simple. I don't want to learn 20 new tools. It will be enough effort to become proficient in OEPE and a database.
I looked at "Oracle Database Tools >> Connecting to an Oracle database" in the help files for OEPE 12.1.1. I tried going through the help files for Database connections, but I got to a "New Connection Profile" form that asks me for a SID, a user name, a password, etc. I don't have any of those. I tried to enter some data in the forms and ping the database, but I could not get any results from the ping. So my first question is: Do I have to sign up for an Oracle database in the cloud or is there a database contained within the OEPE software that I just installed. I will have to do the former anyway when I eventually deploy my new server software, so maybe the right thing to do is sign up for the "database in the cloud" service now, and use it during development.
The other question I have is about getting a simple application client and server application sample. I found a "hello world" example at http://docs.oracle.com/cd/E13224_01/wlw/docs103/guide/webapplications/workshopJSP/tutorialJSP/TutorialJSPMakeJSP.html, but that is for WLS 10.3 and it doesn't seem to match the 12.1.1 software very well.
So does anybody know where I can find a simple client and server sample program for WLS 12.1.1?
If I can get these two questions answered, I can start making some progress.
Thanks in advance to anybody who can help me navigate this minefield.
Jim

Answer 1

I wanted to add some information to my previous posting.
1. The server I will develop will communicate ONLY with Android and iOS native apps, so the interface will not be HTML or XML. The information sent by the server to the client will be JSON. The information sent by the client to the server will be HTTP parameters, usually in the form of URL-encoded form data. This is not a browser-to-server server interface, so JSP is probably not appropriate for the server. The communication protocol will be HTTP.
2. I don't need anything fancy on the server side. The server will simply be a Java program that emits JSON responses to the client and receives URL-encoded form data from the client. The server program will also make database queries and update the database.
3. I don't understand how my native Android app will be able to communicate with my development server code running on my desktop. I want that communication to be over the internet, but my desktop does not have a static IP address, so I don't see how the app will be able to address the development server software on my desktop PC. I don't want to deploy the server software into the cloud every time I start a debug run, but I don't see any other way for my app to be able to address the server code over the Internet.
If anybody has any ideas, I would appreciate hearing them.