JDK 12+ illegal reflective access operation for `Throwable`, `setCause()`

(from mailing list)

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.fasterxml.jackson.databind.util.ClassUtil (...) to method java.lang.Throwable.setCause(java.lang.Throwable)
WARNING: Please consider reporting this to the maintainers of com.fasterxml.jackson.databind.util.ClassUtil
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

This is probably due to deserializer constructed in BeanDeserializerFactory.buildThrowableDeserializer() – ThrowableDeserializer will handle “cause” property by generating a property. It should use initCause(), but perhaps there is non-public setCause() accidentally found…

[edudar]

In my case, this happens with amazon was sdk v1 and databind 2.12.3. Results in runtime exception on Java 16 though, not just warning printout. They try to create an exception from the JSON response like {"__type":"ExpiredTokenException","message":"The security token included in the request is expired"} that causes

java.lang.reflect.InaccessibleObjectException: Unable to make final void java.lang.Throwable.setCause(java.lang.Throwable) accessible: module java.base does not "opens java.lang" to unnamed module @43738a82

[cowtowncoder]

@edudar As usual it’d be necessary to get a reproduction of this: description along is unfortunately not enough. If you can create one, it’d be good to file a separate issue: these typically need to be handled on case-by-case basis as the fundamentally it is not possible to have an overall solution.