[BUG] 500 server error on failed validation of many association

The integration test in the example project shows the error.

https://github.com/tkvw/issue-java8-localtime

The issue is in the master branch:

The test fails because there's a databinding validation error, because there's no supported format for LocalTime by default. Current behaviour: server return 500, expected behaviour: 404 with validation errors.

Start with the integration test in the linked issue-java8-localtime example project and reproduce the failure on the master branch. Trace the databinding validation error for LocalTime and compare the current 500 response with the expected 404 response containing validation errors.

Written by the indexing model from the issue text.