The classes in a JAR file can be made available to a Java application running in a WebSphere application server in the following ways.

• The JAR file can be placed in the applications WEB-INF/lib folder
• The JAR file can be placed in the application servers classpath
• The JAR file can be placed Shared Library

Select Servers > Server Types > WebSphere application servers > your application server > Class loader viewer service and select Enable service at server startup. Restart the application server for this change to take effect.

Navigating to Troubleshooting > Class loader viewer and then select the your WAR.

Expand Module - com.ibm.ws.classloader.CompoundClassLoader > Classpath to view the JAR files being loaded. Additionally, .class files below the "classes" directory will be loaded.

Selecting Classes will display the classes being loaded.

Likewise, if a JAR is deployed to a WebSphere application server, the classes in the JAR can also be seen at Troubleshooting > Class loader viewer, and then select the JAR file.