IBM WebSphere - Setting Classloader Settings (parent last)

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This is step by step guide which shows how to work with IBM WebSphere Classloader Settings.

Goal

Issue: NoClassDefFoundError exception occurring during any action where class indeed exists.

Cause: Class is present but class loader does not "see" the class. Setting Classloader to "parent_last" configuration resolves this issue in most cases.

Pre-Requisites

This on-premise solution requires a team member with access to the IBM console, preferably with administration experience.

Note, Solution is for latest supported WebSphere (8.5.5) as of writing of this article. Consult WebSphere documentation for guidance if the below steps do not take you to the appropriate sections

First Step

Set Classloader Policy at Server level

Log into IBM WebSphere console
Click Servers > Server Types > WebSphere application servers > server_name to access an application server settings page.
Select Classloader Policy: Single
Select Class loading mode: Classes loaded with local class loader first (parent last)
Save changes to master configuration

Second Step

Set Classloader Policy at Manage Modules level

Log into IBM WebSphere console (if not logged in already)
Click Applications > Application Types > WebSphere applications > application_name
Click Manage Modules link
Select module_name
Select Class Loader Order "Classes loaded with class loader first (parent last)
Click Apply
Save changes to master configuration