ResourceProcessorInvoker suffered from Spring's ResolvableType.fromClass(…) using strong assignability checks between raw types and wildcarded right hand side types (i.e. Collection VS. Collection<?>). This has been reported [0] and fixed already but we have to switch to ResolvableType.fromRawClass(…) to get the desired assignment check behavior. Tightened unit tests to verify the calls to the delegate handler, which had been disabled by accident and thus prevented us from detecting the issue with ResolvableType beforehand. [0] https://jira.spring.io/browse/SPR-14648