OPENJPA-758 addressed a class loader issue where ValueHandlers could not be found by an applicable class loader. The fix was specific to ValueHandlers. However, the same issue occurs for other customer mappings (e.g. ClassStrategy, DiscriminatorStrategy, etc). Basically, mappings handled by MappingRepository. I will attach a patch with my proposed changes. The fix is in the same pattern as was done in the fix for JIRA OPENJPA-758, please see this JIRA for more details.