What is Weblogic Server ?
Weblogic server is a java application application server. This is a server that supports various services as well as infrastructure that are related with JEE applications.It is a instance of java process executing in a JVM(Java Virtual Machine). As an application server it exposes business logic to client applications through various protocols, possibly including HTTP and unlike normal Webserver(like Apache, Tomcat..) which just handles HTTP type request, the application server handles business logic of application programs through any number of protocols.
So basically Weblogic server is a software application that runs as a middle tire between back-end database and related applications and browser based thin clients. Think of it as a ATM machine with the user acting as browser thin client and the bank as a database from where it fetches your data.
Oracle acquired WebLogic Server when they purchased BEA Systems in 2008 ergo we usually call it as Oracle Weblogic Server, but you can still see the name BEA in Weblogic server logs if you are already working on it.
Like every software product Weblogic have versions with 12.1.3 being the latest Weblogic version
WebLogic Server 12c Release 3 (12.1.3) – June 26, 2014
WebLogic Server 12c Release 2 (12.1.2) – July 11, 2013
WebLogic Server 12c Release 1 (12.1.1) – Dec 1, 2011
WebLogic Server 11gR1 PS5 (10.3.6) – February 26, 2012
WebLogic Server 11gR1 PS4 (10.3.5) – May 16, 2011
WebLogic Server 11gR1 PS3 (10.3.4) – January 15, 2011
WebLogic Server 11gR1 PS2 (10.3.3) – April 2010
WebLogic Server 11gR1 PS1 (10.3.2) – Nov 2009
WebLogic Server 11g (10.3.1) – Jul 2009
WebLogic Server 10.3 – Aug 2008
WebLogic Server 10.0 – Mar 2007
WebLogic Server 9.2
WebLogic Server 9.1
WebLogic Server 9.0 – Nov 2006
WebLogic Server 8.1 – Jul 2003
WebLogic Server 7.0 – Jun 2002