WebSphere Application Server Network Deployment, Version 6.0.x   Operating Systems: AIX, HP-UX, Linux, Solaris, Windows
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Managing shared libraries

Shared libraries are files used by multiple applications. Each shared library consists of a symbolic name, a Java class path, and a native path for loading Java Native Interface (JNI) libraries. You can use shared libraries to reduce the number of duplicate library files on your system.

About this task

Suppose that you have four applications that use the same library file, my_sample.jar. Instead of having four copies of my_sample.jar on your system after the four applications are deployed, you can define a shared library for my_sample.jar and have the four deployed applications use that one my_sample.jar library file.

Using the administrative console, you can define a shared library.

On a single-server product, you can define a shared library at the cell, node, or server level.

On a multiple-server product, you can define a shared library at the cell, node, server, or cluster level.

A separate class loader is used for shared libraries that are associated with an application server. This class loader is the parent of the application class loader, and the WebSphere Application Server extensions class loader is its parent. Shared libraries that are associated with an application are loaded by the application class loader.

Defining a library at one of the these levels does not automatically place the library into the class loader for an application server. You must associate the library to an application or server before the classes represented by the shared library are loaded into either a server-wide or application-specific class loader.

Using the administrative console, you can then associate the library with an application or server to load the classes represented by the shared library in either a server-wide or application-specific class loader.

Using an installed optional package, you can associate a shared library to an application by declaring the dependent library .jar file in the MANIFEST.MF file of the application. Refer to the Java 2 Platform, Enterprise Edition (J2EE) 1.4 specification, section 8.2 for an example.

If your deployed applications use shared library files, define shared libraries for the library files and associate the libraries with specific applications or with an application server. Associating a shared library file with a server associates the file with all applications on the server. Use the administrative console Shared Libraries page to define new shared library files to the system and to remove existing library files from the system.

Procedure




Sub-topics
Creating shared libraries
Associating shared libraries with applications
Associating shared libraries with servers
Installed optional packages
Using installed optional packages
Related concepts
Class loaders
Related tasks
Configuring native libraries in shared libraries
Related reference
Shared library settings
Task topic    

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Last updated: Mar 8, 2007 8:14:28 PM CST
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