Introduction: Application servers

An application server is a Java Virtual Machine (JVM) that is running user applications. The application server collaborates with the Web server to return a dynamic, customized response to client request. application code, including servlets, JavaServer Pages (JSP) files, enterprise beans and their supporting classes.

For example, given a user at a Web browser on the Internet who visits a company Web site:

  1. The user requests to use an application that provides access to data in a database.
  2. The user request flows to the Web server.
  3. The Web server determines that the request involves an application containing resources not handled directly by the Web server (such as servlets). It forwards the request to WebSphere Application Server.
  4. WebSphere Application Server forwards the request to one of its application servers on which the application is running.
  5. The invoked application then processes the user request. For example:
    • An application servlet prepares the user request for processing by an enterprise bean that performs the database access.
    • The application produces a dynamic Web page containing the results of the user query.
  6. The application server collaborates with the Web server to return the results to the user at the Web browser.

When you install the product, a default application server, named server1, is automatically created. You can use the administrative console to manage this server.

You can use the administrative console or wsadmin commands to create additional application servers that can be either separately configured processes or nearly identical clones. As with server1, you can use the administrative console to mange these additional servers.

You can define multiple application servers, each running its own JVM. You can also use the following options to enhance the operation of an application server:

To begin creating and managing an application server, see Administering application servers.

Asynchronous messaging

The product supports asynchronous messaging based on the Java Message Service (JMS) of a JMS provider that conforms to the JMS specification version 1.1.

The JMS functions of the default message service in WebSphere Application Server are served by one or more messaging engines (in a service integration bus) that runs within application servers.

In a deployment manager cell, there can be WebSphere Application Server version 5 nodes. If a version 5 node is configured to use V5 default messaging (the version 5 embedded messaging), there can be at most one JMS server on that node.

Generic Servers

A generic server is a server that is managed in the WebSphere administrative domain, although it is not a server that is supplied by the WebSphere Application Server product. The generic server can be any server or process that is necessary to support the Application Server environment.

For more information, refer to Creating generic servers.




Related concepts
Introduction: Application servers
Related tasks
Creating generic servers
Programming to use JMS and messaging directly
Administering application servers
Configuring transport chains
Creating custom services
Tuning application servers
Managing Object Request Brokers
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Last updatedLast updated: Aug 30, 2013 10:47:11 PM CDT
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