JSONObject(Map) handling of null keys

[jwagenleitner]

The JSONObject's map based constructor does not throw an exception when the Map contains null keys.

The following will fail the NotNull check.

        HashMap m = new HashMap();
        m.put("foo", "bar");
        m.put(null, "oops");

        JSONObject json = new JSONObject(m);

        assertNotNull(json.toString());
        assertEquals("{\"foo\":\"bar\"}", json.toString());

And the following will fail the Equals check:

        HashMap mFoo = new HashMap();
        mFoo.put("one", "two");
        mFoo.put(null, "three");

        HashMap m = new HashMap();
        m.put("foo", mFoo);

        JSONObject json = new JSONObject(m);

        assertNotNull(json.toString());
        assertEquals("{\"foo\":{\"one\":\"two\"}}", json.toString());  // actual is {"foo":null}

I am interested to know if the current behavior is by design or if an exception is meant to be thrown since the javadocs for the constructor says it throws a JSONException but it doesn't declare that it throws it.

[douglascrockford]

The HashMap constructor is provided as a convenience. It assumes that you know what you are doing.

[jwagenleitner]

That was my suspicion, thanks for the clarification.