Check the method org.jboss.resteasy.util.StringToPrimitive.stringToPrimitiveBoxType(Class primitiveType, String value)
it misses case for char primitive.
this means that in this kind of method

@Path("/")
public class ParamTestResource {
@GET
@Path("/pathparam8/

")
public String pathparam(@PathParam("var") char var)

}

var is always injected null value.