Jersey throws NullPointerException when parsing corrupt request

Question

When sending a request with content type multipart/mixed but corrupt body (one that is no multipart), Jersey throws a `NullPointerException` while parsing the request. ``` @POST @Consumes("multipart/mixed") public Response someResource(MultiPart multiPart) { ... } ``` This results in a status code 500, while 4xx would be correct. How can I handle this exception without catching all `NullPointerExceptions`? Attachment A: stacktrace: ``` SEVERE: The RuntimeException could not be mapped to a response, re-throwing to the HTTP container java.lang.NullPointerException at com.sun.jersey.multipart.impl.MultiPartReaderClientSide.unquoteMediaTypeParameters(MultiPartReaderClientSide.java:227) at com.sun.jersey.multipart.impl.MultiPartReaderClientSide.readMultiPart(MultiPartReaderClientSide.java:154) at com.sun.jersey.multipart.impl.MultiPartReaderServerSide.readMultiPart(MultiPartReaderServerSide.java:80) at com.sun.jersey.multipart.impl.MultiPartReaderClientSide.readFrom(MultiPartReaderClientSi…

Accepted Answer

This seems to be a bug in Jersey. They don't check the "boundary" parameter value for `null`, before dereferencing it. You will have to find a workaround until it is fixed.

Workaround 1: Provide an `ExceptionMapper`

Maybe you can register an `ExceptionMapper` for `NullPointerException` and inspect the stack trace to test, if it is that bug or any other NPE. In case of this bug, return `4xx`, otherwise as usual `500 - internal server error`. (It's a bad hack, but I think that's ok for a temporary workaround).

Workaround 2: Provide a JAX-RS `ContainerRequestFilter`

Since JAX-RS 2.0, it is possible to provide a `ContainerRequestFilter` that is invoked before the resource method is called. Check the boundary parameter in the `Content-Type` request header. If it is absent, abort the request by calling `ContainerRequestContext#abortWith(Reponse)`.

Workaround 3: Write a servlet filter

Similar to workaround 2, but with good-old `javax.servlet.Filter`. Make sure, the filter is called before Jersey processes the request.

Jersey throws NullPointerException when parsing corrupt request

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