Hi,
I have a JAX-RS method which receives a multipart/form-data parameter via @MultipartForm annotation.

One of the parameters is an Integer, but when the value comes empty in the request, the conversion fails on TypeConverter.

This is the exception:
11:08:29,753 WARN [org.jboss.resteasy.core.SynchronousDispatcher] (http-localhost/127.0.0.1:8080-2) Failed executing POST /test/method: org.jboss.resteasy.spi.ReaderException: org.jboss.resteasy.core.ExceptionAdapter: : null
at org.jboss.resteasy.core.MessageBodyParameterInjector.inject(MessageBodyParameterInjector.java:202) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.core.MethodInjectorImpl.injectArguments(MethodInjectorImpl.java:136) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.core.MethodInjectorImpl.invoke(MethodInjectorImpl.java:159) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.core.ResourceMethod.invokeOnTarget(ResourceMethod.java:269) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.core.ResourceMethod.invoke(ResourceMethod.java:227) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.core.ResourceMethod.invoke(ResourceMethod.java:216) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.core.SynchronousDispatcher.getResponse(SynchronousDispatcher.java:542) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:524) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:126) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:208) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:55) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:50) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) [jboss-servlet-api_3.0_spec-1.0.2.Final-redhat-1.jar:1.0.2.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:295) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
at bps.atyr.acerca.serviciodomestico.movil.filters.CORSFilter.doFilter(CORSFilter.java:40) [classes:]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:149) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
at org.jboss.as.jpa.interceptor.WebNonTxEmCloserValve.invoke(WebNonTxEmCloserValve.java:50) [jboss-as-jpa-7.2.0.Final-redhat-8.jar:7.2.0.Final-redhat-8]
at org.jboss.as.jpa.interceptor.WebNonTxEmCloserValve.invoke(WebNonTxEmCloserValve.java:50) [jboss-as-jpa-7.2.0.Final-redhat-8.jar:7.2.0.Final-redhat-8]
at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:169) [jboss-as-web-7.2.0.Final-redhat-8.jar:7.2.0.Final-redhat-8]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:145) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:97) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:559) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:102) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:336) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:856) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:653) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:920) [jbossweb-7.2.0.Final-redhat-1.jar:7.2.0.Final-redhat-1]
at java.lang.Thread.run(Unknown Source) [rt.jar:1.6.0_27]
Caused by: org.jboss.resteasy.core.ExceptionAdapter: : null
at org.jboss.resteasy.util.TypeConverter.getTypeViaValueOfMethod(TypeConverter.java:212) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.util.TypeConverter.getType(TypeConverter.java:79) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.plugins.providers.DefaultTextPlain.readFrom(DefaultTextPlain.java:38) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.plugins.providers.multipart.MultipartInputImpl$PartImpl.getBody(MultipartInputImpl.java:290) [resteasy-multipart-provider-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.plugins.providers.multipart.MultipartFormAnnotationReader.readFrom(MultipartFormAnnotationReader.java:105) [resteasy-multipart-provider-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.core.interception.MessageBodyReaderContextImpl.proceed(MessageBodyReaderContextImpl.java:105) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.plugins.interceptors.encoding.GZIPDecodingInterceptor.read(GZIPDecodingInterceptor.java:63) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.core.interception.MessageBodyReaderContextImpl.proceed(MessageBodyReaderContextImpl.java:108) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
at org.jboss.resteasy.core.MessageBodyParameterInjector.inject(MessageBodyParameterInjector.java:169) [resteasy-jaxrs-2.3.6.Final-redhat-1.jar:2.3.6.Final-redhat-1]
... 31 more

This is a minimal code to reproduce the error.
The service:
@Stateless
@Path("/test")
public class WsTest {

@POST
@Path("/method")
@Consumes("multipart/form-data")
@Produces(MediaType.APPLICATION_JSON)
public Response testPost( @MultipartForm TestParam param
)

}

The TestParam class:

public class TestParam {

private Integer jornales;

public Integer getJornales()

@FormParam("jornales")
public void setJornales(Integer jornales)

}

And the request:
POST /sdmovil/test/method HTTP/1.1
Host: localhost:8080
Origin: file://
Content-Type: multipart/form-data; boundary=----WebKitFormBoundarybxtEqUk8vCjKWf5O
Cache-Control: no-cache

-----WebKitFormBoundarybxtEqUk8vCjKWf5O Content-Disposition: form-data; name="jornales" ------WebKitFormBoundarybxtEqUk8vCjKWf5O-

With this request, the server fails to convert the value, instead of assigning a null value to the attribute. AFAIK it should assign null to the value and continue the excecution normally.
If I set the value of the parameter, as follows, it works fine:

------WebKitFormBoundarybxtEqUk8vCjKWf5O
Content-Disposition: form-data; name="jornales"
1
-----WebKitFormBoundarybxtEqUk8vCjKWf5O-

Also, changing the type from Integer to String works as well, assigning an empty string to the attribute.

I hope I made myself clear, and this can be reproduced and fixed.

Thanks in advance.
Regards.