Major Description
The default JSONProvider is trying to marshal a non-jaxb class which results in a 500 response of my endpoint.
One of my endpoints is returning a StreamingOutput object to the response object:
public static Response okJson(JValue json) {
return Response.ok(new StreamingOutput() {
@Override
public void write(OutputStream s) throws IOException, WebApplicationException {
try (final BufferedOutputStream bs = new BufferedOutputStream(s)) {
serializer.fn.toJson(json).apply(bs);
}
}
}, MediaType.APPLICATION_JSON_TYPE).build();
}
Unfortunately, the default JSONProvider is trying to marshal this class because it thinks it is a jaxb supported class. This support check happens in the AbstractJAXBProvider class:
protected boolean isSupported(Class<?> type, Type genericType, Annotation[] anns) {
if (jaxbElementClassMap != null && jaxbElementClassMap.containsKey(type.getName())
|| isSkipJaxbChecks()) {
return true;
}
return isXmlRoot(type)
|| JAXBElement.class.isAssignableFrom(type)
|| objectFactoryOrIndexAvailable(type)
|| (type != genericType && objectFactoryForType(genericType))
|| org.apache.cxf.jaxrs.utils.JAXBUtils.getAdapter(type, anns) != null;
}
protected boolean objectFactoryOrIndexAvailable(Class<?> type) {
return type.getResource("ObjectFactory.class") != null
|| type.getResource("jaxb.index") != null;
}
The issue is that the objectFactoryOrIndexAvailable is returning true which doesn't indicate that the type itself is a jaxb class. To fix the support method it should actually check if there is a jaxb.index file and if in the index file the current type is available. Then we can clearly say it's a jaxb supported class.
Something like this:
return isXmlRoot(type)
|| JAXBElement.class.isAssignableFrom(type)
|| (objectFactoryOrIndexAvailable(type) && indexContainsType(type))
|| (type != genericType && objectFactoryForType(genericType))
|| org.apache.cxf.jaxrs.utils.JAXBUtils.getAdapter(type, anns) != null;
protected boolean indexContainsType(Class<?> type) {
try (BufferedReader reader = new BufferedReader(new InputStreamReader(type.getResourceAsStream("jaxb.index")))) {
String line = null;
while((line = reader.readLine()) != null) {
if(line.contains(type.getName()))
return true;
}
}
return false;
}