Volley JSONException: End of input at character 0 of

Might not make sense but nothing else worked for me but adding a content-type header

mHeaders.put("Content-Type", "application/json");

I also have encountered this issue.

It's not necessarily true that this is because a problem on your server side - it simply means that the response of the JsonObjectRequest is empty.

It could very well be that the server should be sending you content, and the fact that its response is empty is a bug. If, however, this is how the server is supposed to behave, then to solve this issue, you will need to change how JsonObjectRequest parses its response, meaning creating a subclass of JsonObjectRequest, and overriding the parseNetworkResponse to the example below.

    @Override
    protected Response<JSONObject> parseNetworkResponse(NetworkResponse response) {
        try {
            String jsonString = new String(response.data,
                    HttpHeaderParser.parseCharset(response.headers, PROTOCOL_CHARSET));

            JSONObject result = null;

            if (jsonString != null && jsonString.length() > 0)
                 result = new JSONObject(jsonString);

            return Response.success(result,
                    HttpHeaderParser.parseCacheHeaders(response));
        } catch (UnsupportedEncodingException e) {
            return Response.error(new ParseError(e));
        } catch (JSONException je) {
            return Response.error(new ParseError(je));
        }
    } 

Keep in mind that with this fix, and in the event of an empty response from the server, the request callback will return a null reference in place of the JSONObject.