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Does anyone know how to update the content of a WebLogic Server's WLS_HOME/server/lib/ folder without having to restart it?

A colleague of mine did a deployment which involved an updated .jar file that was used by all the .ears in the user_projects directory, so he decided to place it in WLS_HOME/server/lib. Whilst the web apps he deployed to user_projects deployed ok, we noticed in the server log it was getting repeated NoClassDefFound exceptions for classes we knew were in the updated .jar - and it didn't pick up the new classes till after a restart.

I need ideally to be able to deploy new shared libraries to this /lib folder without having to restart the server as that involves an outage.

Does anyone know how to do this?

Arjan Tijms
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Matt Moran
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1 Answers1

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This is not possible. You should move to shared Java EE libraries if you need more flexibility. For your current situation, the only thing you can do, provided you have a clustered environment, is to do a rolling restart of the instances to avoid downtime.

From Understanding WebLogic Server Application Classloading :

WebLogic Server includes a lib subdirectory, located in the domain directory, that you can use to add one or more JAR files to the WebLogic Server system classpath when servers start up. The lib subdirectory is intended for JAR files that change infrequently and are required by all or most applications deployed in the server, or by WebLogic Server itself. For example, you might use the lib directory to store third-party utility classes that are required by all deployments in a domain. You can also use it to apply patches to WebLogic Server.

The lib directory is not recommended as a general-purpose method for sharing a JARs between one or two applications deployed in a domain, or for sharing JARs that need to be updated periodically. If you update a JAR in the lib directory, you must reboot all servers in the domain in order for applications to realize the change. If you need to share a JAR file or Java EE modules among several applications, use the Java EE libraries feature described in Creating Shared Java EE Libraries and Optional Packages.

Arjan Tijms
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ddewaele
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  • Ah, thanks - I thought that was probably the case, but I wanted to throw it out there just in case anyone'd come up with a hack to make it load them without a restart. We did a rollout on a live system where ideally we don't want to restart ever, but using WLS's scripting interface got it to deploy the webapps. There's no way to script reloading the server/lib jars then? – Matt Moran Jul 28 '11 at 11:30