Had the same issue when defining my own AnnotationMethodHandlerAdapter so I could register custom messageConverters. The
tag I had used for registering a validator and conversion service created its own AnnotationMethodHandlerAdapter, put it at order #0, and my message converters were never used.
Took me a while to track it down to the same thing; took out the
tag and defined all my own stuff using this instead:
Hope that helps someone not spend an hour or two tracking it down...
<property name="conversionService" ref="customConversionService"/>
<property name="validator" ref="customValidator"/>