Sun Java System Application Server Enterprise Edition 8.1 2005Q2 Upgrade and Migration Guide

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## Deployment of Migrated Applications

Deployment refers to deploying a migrated application that was previously deployed on an earlier version of Sun’s Application Server, or any third party application server platforms.

To be able to deploy your migrated applications on Application Server 8.1, it is important to understand classloaders in Application Server 8.1 and changes to the architecture of Application Server 8.1.

In Application Server 7, the DAS controls multiple local instances. The Common Classloader loads the classes in the install-dir/<yourdomain>/<yourinstance>/`lib`/`classes` directory and the install-dir/<yourdomain>/<yourinstance>/`lib` directory. All resources and configurations correspond to a specific instance.

In Application Server 8.1, the DAS controls local and remote instances. The Common Classloader loads the JAR and ZIP files in the domain-dir/`lib` directory and the classes in the domain-dir/`lib/classes` directory.

In Application Server 8.1, any JAR file placed in the `lib` directory of the DAS is replicated to all instances controlled by that DAS. The JAR files bundled with the Application Server reside in the install-dir/`lib` directory.

For more information on the classloader hierarchy in Application Server 8.1, see The Classloader Hierarchy in Sun Java System Application Server Enterprise Edition 8.1 2005Q2 Developer’s Guide.

You can use the delegation inversion mechanism to use libraries bundled with your application instead of those bundled with the Application Server. However, it is safe to use this mechanism only for web modules that do not access EJB components and do not interact with other applications. For more information on the delegation model of Application Server 8.1, see Classloader Delegation in Sun Java System Application Server Enterprise Edition 8.1 2005Q2 Developer’s Guide.

Note –

The default value of the `delegate` attribute is `true` in Application Server 8.1. See Sun Deployment Descriptor: sun-web.xml.

The JAXP 1.3 parser is bundled with Application Server 8.1. You cannot override the JAXP 1.3 parser for Application Server 8.1.

In Application Server 8.1, to share a library with all the applications and modules in a domain, place the libraries (JAR files) in the domain-dir/`lib` directory and restart the Application Server. The Common Classloader will load the new libraries. Use this approach to share commonly shared libraries, such as JDBC drivers.

To share libraries across a specific cluster instead of over an entire domain, add the JAR files to the domain-dir/`config`/<cluster-name>`-config`/`lib` directory and add the path to the JAR files in the `classpath-suffix` attribute. For instructions on how to change this attribute, see Using the System Classloader in Sun Java System Application Server Enterprise Edition 8.1 2005Q2 Developer’s Guide.

Copy the JAR files to domain-dir/`config`/<cluster-name>`-config`/`lib`/`ext` directory to add to `java.ext.dirs`. To create an optional package that can be shared across the domain, add the JAR file to domain-dir/`lib`/`ext` directory and restart the Application Server.

Note –

If multiple applications deployed on a single instance require different versions of the same JAR file, ensure that those JAR files have different names.

- Previous: What Needs to be Migrated
- Next: Chapter 5 Migrating from EJB 1.1 to EJB 2.0

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