Java Development Tools

All,
I have some question about WebLogic Server:

- which is the latest version ? Is the 12 C the current one ?
- as registered BEA user, where can I find the related download ? For our OpenSuse Linux x86-64bit I find for example:

--> Oracle WebLogic Server 11gR1 (10.3.1) for Linux x86 in the Oracle® Application Server 10g Release 3 (10.1.3) Media Pack for Linux x86 folder, but also:
--> Oracle WebLogic Server 11gR1 (10.3.3) Generic in the Oracle Fusion Middleware 11g Media Pack for Linux x86-64
Which one should I install ?

- is the latest version compatible with JDeveloper 11G R2 11.1.2.1.0 ?

We are experiencing a performance decay in our application.

When the WebLogic Server (we are using version 10.3.5.0 ) has been started, our (intranet) web application runs flawless and fast; however, as we continue to use the application, the performance decays: for example, the data visualization slows down, it takes much more time to display a simple page, and so on.

The entire application then slows down at a point, that we have to re-start the whole WebLogic Server in order to use it.

The question: is any optimization required for WebLogic Server, in order to have a constant performance ?

Does the new WebLogic Server (12 C ?) perform faster, or at least constant ?

Thanks in advance,
Sergio.