Steps to reproduce
Perform a request to set a variable of type file with value null against an REST API endpoint of your choice. For instance POST /process-definition/$ID/start

{"variables": {"fileVariable":{"value":null,"type":"File","valueInfo":{"filename":"aFileName.txt"}}}}

Observed behavior
The IllegalArgumentException is not catched and therefore propagated to the JAX-RS provider which leads to an html response body including a stacktrace

Expected behavior
The exception is handled properly