What is a WebLogic Server Explained – Part 2
I have explained the Fundamentals of the use of a WebLogic Server in Part 1 here. This post explains things with some extended details. 
WebLogic Server has different components . All these components are Java process. The Components are –
1. Domain
- Domain(s) are the Most primitive building blocks of a WebLogic server
- Each domain MUST have ONE SINGLE Admin Server.
- Domain might also contain zero or No Managerd Servers. Managed servers can further be Clustered based on need
- Based on Business or Functional need , you can span out the applications across various domains.
2. Admin Server
- It is an web-based Interface to administer the Domain.
- You can also use WLST (WebLogic Scripting Tool) if you prefer script based administion .
- Allows deployment and configuration of various resources such as adapters, jndi name configuration, connection pools etc.
- Managed servers refer to the Admin server for configuration
3. Managed Server
- This Java environment runs your actual Application.
- You can create Clusters of Managed Servers.
- It can be a OBIEE(Oracle Business Intelligence Enterprise Edition) or Data Integrator or a Service Bus etc.
- If you want High Availability or Fault-Tolerance , it is a good idea to deploy the Application onto more than one Managed server (Clustered or Non-Clustered)
Web Server , Application Server vs WebLogic Server
- Web Server - Serves HTTP content.It mostly stores the Static Contents. E.g. Nginx or even Python's SimpleHTTPServer
- Application Server – Hosts the Application(s) or Business Logic.
- WebLogic Server – It bundles both Web Server & the Application Server. It is Oracle’s product. Competitor’s are – IBM WebSphere , Redhat JBoss & Apache Tomcat