안드로이드 스튜디오 Log 오류

Question

java.lang.NullPointerException: println needs a message
                      at android.util.Log.println_native(Native Method)
                      at android.util.Log.d(Log.java:164)
                      at com.example.eoqn9_000.ecobus.SampleActivity21$1$1.run(SampleActivity21.java:83)
                      at android.os.Handler.handleCallback(Handler.java:739)
                      at android.os.Handler.dispatchMessage(Handler.java:95)
                      at android.os.Looper.loop(Looper.java:145)
                      at android.app.ActivityThread.main(ActivityThread.java:5942)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at java.lang.reflect.Method.invoke(Method.java:372)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
I/System.out: (HTTPLog)-Static: isSBSettingEnabled false
I/System.out: (HTTPLog)-Static: isShipBuild true
I/System.out: (HTTPLog)-Thread-36421-92049416: SmartBonding Enabling is false, SHIP_BUILD is true, log to file is false, DBG is false
I/System.out: (HTTPLog)-Static: isSBSettingEnabled false
I/System.out: KnoxVpnUidStorageknoxVpnSupported API value returned is false

위 에러가 계속 뜨는데 아래코드가  뭐가  잘못된건지 정말 못찾겠네요 ㅜㅜ

도와주세요

 

 

 

private String x;
        @Override
        public void run () {
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    gps();
                  getDbData();
                    Log.d("z",x);
                    reset();



                }
            });
        }
    };
    mTimer = new Timer();
    mTimer.schedule(mTask, 5000,5000);
}

    protected void getDbData() {
        class OutData extends AsyncTask<String, Void, String> {
            @Override
            protected String doInBackground(String... params) {
                StringBuilder jsonHtml = new StringBuilder();

                try {
                    String link = "http://xx.xxxx.xxxx/zzz0.php?id=" + stationId;
                    URL phpUrl = new URL(link);
                    HttpURLConnection conn = (HttpURLConnection) phpUrl.openConnection();
                    if (conn != null) {
                        conn.setConnectTimeout(10000);
                        conn.setUseCaches(false);
                        if (conn.getResponseCode() == HttpURLConnection.HTTP_OK) {
                            BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8"));
                            while (true) {
                                String line = br.readLine();
                                if (line == null)
                                    break;
                                jsonHtml.append(line + "\n");
                            }
                            br.close();
                        }
                        conn.disconnect();
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
                return jsonHtml.toString();
            }

            protected void onPostExecute(String str) {
                dbData = str;
                getData();
            }

        }
        OutData g = new OutData();
        g.execute();
        }

    protected void getData(){
        try {
            JSONObject ja = new JSONObject(dbData);
            peoples = ja.getJSONArray(TAG_RESULTS);

            for(int i=0; i<ja.length(); i++){
                JSONObject jo = peoples.getJSONObject(i);
                x = jo.getString("x");
                y = jo.getString("y");
                sign = jo.getString("sign");

            }

        }catch (JSONException e){
            e.printStackTrace();
        }
        return;
    }