Java - JSON Null Exception

Question

Hi,

I'm using JSON to deserialize an input string that contains a null value for certain hashmap property. Does anyone have any clue why this exception occurs ? Is it possible that null is not accepted as a value Is this configurable somehow ?

input sample:

{"prop1":"val1", "prop2":123, "prop3":null}

stacktrace:

net.sf.json.JSONException: null object
    at net.sf.json.JSONObject.verifyIsNull(JSONObject.java:2856)
    at net.sf.json.JSONObject.isEmpty(JSONObject.java:2212)

Thanks.

Answer 1

For me this works with json-lib-2.3-jdk15:

String json = "{\"prop1\":\"val1\", \"prop2\":123, \"prop3\":null}";
JSONObject jsonObject = JSONObject.fromObject(json);
HashMap<String, Object> map = (HashMap<String, Object>) JSONObject.toBean(jsonObject, HashMap.class);

Actually the null value becomes an instance of JSONNull.

JSONNull is equivalent to the value that JavaScript calls null, whilst Java's null is equivalent to the value that JavaScript calls undefined.