Java Server Pages (JSP) in breif

JavaServer Pages (JSP) is a technology based on the Java language and enables the development of dynamic web sites. JSP was developed by Sun Microsystems to allow server side development. JSP files are HTML files with special Tagscontaining Java source code that provide the dynamic content.

JSP source code runs on the web server in the JSP Servlet Engine. The JSP Servlet engine dynamically generates the HTML and sends the HTML output to the client’s web browser.

JSP is based on Java, an objectoriented language. JSP offers a robust platform for web development. JSP code on the server is classed as the implementation. By having a separation of presentation and implementation, designers work only on the presentation and developers concentrate on implementing the application.

JSPs are built on top of SUN’s servlet technology. JSPs are essential an HTML page with special JSP tags embedded. These JSP tags can contain Java code. The JSP file extension is .jsp rather than .htm or .html. The JSP engine parses the .jsp and creates a Java servlet source file. It then compiles the source file into a class file, this is done the first time and this why the JSP is probably slower the first time it is accessed. Any time after this the special compiled servlet is executed and is therefore returns faster.

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WebLogic Server Deployment Modes

Staging Modes in WebLogic Server

Stage mode

The Administration Server copies the archive files from their source location to a location on each of the targeted Managed Servers that deploy the archive. Consider if you deploy a J2EE Application to three servers in a cluster, the Administration Server copies the application archive files to each of the three servers. Each server then deploys the J2EE Application using its local copy of the archive files.

* Stage mode is the default mode when deploying to more than one WebLogic Server instance.

External Stage mode

External stage mode is similar to stage mode, but in that the deployment files must reside locally to each targeted server. Here Administration Server does not automatically copy the deployment files to targeted servers in external stage mode, instead we must manually copy the files, or use a third-party application to copy the files for you.

NoStage mode

The Administration Server does not copy the archive files from their source location. Instead, each targeted server must access the archive files from a single source directory for deployment. If you deploy a J2EE Application to three servers in a cluster, each server must be able to access the same application archive files (from a shared or network-mounted directory) to deploy the application.

* Nostage mode is the default mode when deploying only to the Administration Server (for example, in a single-server domain). You can also select nostage mode if you run a cluster of server instances on the same machine.

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