How to send JSONobject over TCP?
You are using an ObjectOutputStream to serialize your data. That serialization uses it's own implementation of converting Serializable objects to a byte representation that is then sent through your socket.
JSON is used to serialize an object into a String representation. Unfortunately, you never use the json serialization but instead try to send your JSON object through your socket.
My suggestion: turn your object to a String using
String strJson = jsonObject.toString();then send a String using your ObjectOutputStream. On the receiving end read it as a String, then turn it back into a JSONObject by passing that String to the constructor:
JSONObject js = new JSONObject(strJson);