How to: force loading "managed server wide" jar library in Weblogic

To force loading custom java jar library on application server start, usually you have to put jar file to appropriate folder of the application server. For example:

Apache Tomcat 5.5: [SERVER_DIR]/common/classes/
Apache Tomcat 6.x: [SERVER_DIR]/lib/
jBoss 4.x, 5.x: [SERVER_DIR]/server/[SERVER_TYPE]/conf/
Glassfish 2.x, 3.x: [SERVER_DIR]/domain/[DOMAIN]/lib/classes/

In the case of Weblogic 11g/12c server you can force loading of jar library on all managed servers in the domain by putting file to folder

[DOMAIN_DIR]/lib

You can also configure each managed server separately to load library by putting path to jar in managed server classpath. To do this run weblogic server administration console and next go to Environment | Servers | (Configuration Tab) | Selected_Server. Go to managed server configuration and find Server Start tab. The below image shows where you can put path to jar file: