Creating shared libraries

Shared libraries are files used by multiple applications. Create a shared library to reduce the number of duplicate library files on your system.

Before you begin

Determine the full path name or directory of each library file for which you want a shared library.

About this task

To make a library file available to multiple applications deployed on a server, create one or more shared libraries for library files that your applications need. When you create the shared libraries, you can use variables within the library file class paths.

You can create one shared library that points to multiple files or directories. This enables you to maintain a single shared library for files that your applications need.

Or you can create a shared library for each library file that your applications need. This approach is recommended only when you have few library files and few applications that use the files. After you create a shared library, you associate it with each application that uses the library files. If you have multiple shared libraries and multiple applications that use the library files, you must complete many steps to create and associate those shared libraries. It is simpler to use one shared library for related files.

Use the Shared libraries page to create and configure shared libraries.

Procedure

Go to the Shared libraries page.
Click Environment > Shared libraries in the console navigation tree.
Select a shared library scope.
Change the scope of the collection table to see what shared libraries are in a particular cell, node or server.
1. Select a cell, node, or server.
  On a multiple-server product, you also can select a cluster. To see the cluster scope, you first must create a cluster on the Server clusters page (Servers > Clusters > WebSphere application server clusters).
2. Click Apply.
After creating a shared library, you can see whether a shared library can be used on a specific node. Select a scope to see what shared libraries are available to applications installed on or mapped to that scope.
Click New.
Configure the shared library.
1. On the shared library settings page, specify the name, class path, and any other variables for the library file that are needed.
  If the shared library specifies a native library path, refer to Configuring native libraries in shared libraries.
  
  To have only one instance of a version of a class shared among applications or modules, make the shared library an isolated shared library. Select Use an isolated class loader for this shared library. Using an isolated shared library can reduce the memory footprint when a large number of applications share the library.
2. Click Apply.

What to do next

Using the administrative console, associate your shared libraries with specific applications or modules or with the class loader of an application server. Associating a shared library file with a server class loader associates the file with all applications on the server.

If you enabled the Use an isolated class loader for this shared library setting when creating your shared library, associate the shared library with applications or web modules. To override this behavior for a specific shared library, add -Dcom.ibm.ws.classloader.useNonIsolatedSharedLibrariesForServer=true as a generic JVM argument to your server JVM settings, or deselect the Use an isolated class loader for this shared library setting for that library. If the override property is set, libraries associated with the server class loader do not use an isolated class loader.

Alternatively, you can use an installed optional package to associate your shared libraries with an application.