JavaType rootType, JsonDeserializer<Object> deser)
throws IOException, JsonParseException, JsonMappingException
{
String expName = config.getRootName();
if (expName == null) {
SerializedString sstr = _rootNames.findRootName(rootType, config);
expName = sstr.getValue();
}
if (jp.getCurrentToken() != JsonToken.START_OBJECT) {
throw JsonMappingException.from(jp, "Current token not START_OBJECT (needed to unwrap root name '"
+expName+"'), but "+jp.getCurrentToken());
}