java.io.IOException: Received authentication challenge is null

Question

I need get a response code, but it's throw a IOException. I don't know what's the matter!

    try
    {
        url = new URL(urlBuilder.toString());
        conn = (HttpURLConnection) url.openConnection();
        conn.setDoInput(true);
        conn.setConnectTimeout(TIME_OUT);
        conn.setRequestMethod(METHOD_GET);
        conn.setRequestProperty("accept", "*/*");
        conn.connect();
        int responseCode = conn.getResponseCode();   //throw IOException:Received authentication challenge is null
        if (responseCode == HTTP_OK)
        {
            inStream = conn.getInputStream();
            response = getResponse(inStream);
        }
        else
        {
            response = "response code："+responseCode;
        }
    } catch (Exception e)
    {
        throw e;
    }
    finally
    {
        conn.disconnect();
    }
    return response;
}

the IOException is :

05-03 20:14:01.577: WARN/System.err(1515): java.io.IOException: Received authentication challenge is null
05-03 20:14:01.596: WARN/System.err(1515):     at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.doRequestInternal(HttpURLConnectionImpl.java:1694)
05-03 20:14:01.577: INFO/QQWeiBo(1515): Received authentication challenge is null
05-03 20:14:01.577: WARN/System.err(1515): java.io.IOException: Received authentication challenge is null
05-03 20:14:01.577: WARN/System.err(1515): java.io.IOException: Received authentication challenge is null
05-03 20:14:01.596: WARN/System.err(1515):     at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.doRequestInternal(HttpURLConnectionImpl.java:1694)
05-03 20:14:01.596: WARN/System.err(1515):     at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.doRequest(HttpURLConnectionImpl.java:1649)
05-03 20:14:01.596: WARN/System.err(1515):     at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.getResponseCode(HttpURLConnectionImpl.java:1374)
05-03 20:14:01.596: WARN/System.err(1515):     at com.szy.weibo.service.SyncHttp.httpGet(SyncHttp.java:72)
05-03 20:14:01.596: WARN/System.err(1515):     at com.szy.weibo.service.Weibo.getRequestToken(Weibo.java:45)
05-03 20:14:01.606: WARN/System.err(1515):     at com.szy.weibo.MainActivity.startWebView(MainActivity.java:95)
05-03 20:14:01.606: WARN/System.err(1515):     at com.szy.weibo.MainActivity.authorization(MainActivity.java:83)
05-03 20:14:01.606: WARN/System.err(1515):     at com.szy.weibo.MainActivity$1.onClick(MainActivity.java:71)
05-03 20:14:01.606: WARN/System.err(1515):     at android.view.View.performClick(View.java:2408)
05-03 20:14:01.596: WARN/System.err(1515):     at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.doRequestInternal(HttpURLConnectionImpl.java:1694)
05-03 20:14:01.596: WARN/System.err(1515):     at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.doRequest(HttpURLConnectionImpl.java:1649)
05-03 20:14:01.596: WARN/System.err(1515):     at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.getResponseCode(HttpURLConnectionImpl.java:1374)
05-03 20:14:01.596: WARN/System.err(1515):     at com.szy.weibo.service.SyncHttp.httpGet(SyncHttp.java:72)
05-03 20:14:01.596: WARN/System.err(1515):     at com.szy.weibo.service.Weibo.getRequestToken(Weibo.java:45)
05-03 20:14:01.606: WARN/System.err(1515):     at com.szy.weibo.MainActivity.startWebView(MainActivity.java:95)
05-03 20:14:01.606: WARN/System.err(1515):     at com.szy.weibo.MainActivity.authorization(MainActivity.java:83)
05-03 20:14:01.606: WARN/System.err(1515):     at com.szy.weibo.MainActivity$1.onClick(MainActivity.java:71)
05-03 20:14:01.606: WARN/System.err(1515):     at android.view.View.performClick(View.java:2408)
05-03 20:14:01.596: WARN/System.err(1515):     at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.doRequest(HttpURLConnectionImpl.java:1649)
05-03 20:14:01.596: WARN/System.err(1515):     at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl.getResponseCode(HttpURLConnectionImpl.java:1374)
05-03 20:14:01.596: WARN/System.err(1515):     at com.szy.weibo.service.SyncHttp.httpGet(SyncHttp.java:72)
05-03 20:14:01.596: WARN/System.err(1515):     at com.szy.weibo.service.Weibo.getRequestToken(Weibo.java:45)
05-03 20:14:01.606: WARN/System.err(1515):     at com.szy.weibo.MainActivity.startWebView(MainActivity.java:95)
05-03 20:14:01.606: WARN/System.err(1515):     at com.szy.weibo.MainActivity.authorization(MainActivity.java:83)
05-03 20:14:01.606: WARN/System.err(1515):     at com.szy.weibo.MainActivity$1.onClick(MainActivity.java:71)
05-03 20:14:01.606: WARN/System.err(1515):     at android.view.View.performClick(View.java:2408)
05-03 20:14:01.606: WARN/System.err(1515):     at android.view.View$PerformClick.run(View.java:8816)
05-03 20:14:01.616: WARN/System.err(1515):     at android.os.Handler.handleCallback(Handler.java:587)
05-03 20:14:01.627: WARN/System.err(1515):     at android.os.Handler.dispatchMessage(Handler.java:92)
05-03 20:14:01.627: WARN/System.err(1515):     at android.os.Looper.loop(Looper.java:123)
05-03 20:14:01.627: WARN/System.err(1515):     at android.app.ActivityThread.main(ActivityThread.java:4627)
05-03 20:14:01.627: WARN/System.err(1515):     at java.lang.reflect.Method.invokeNative(Native Method)
05-03 20:14:01.606: WARN/System.err(1515):     at android.view.View$PerformClick.run(View.java:8816)
05-03 20:14:01.616: WARN/System.err(1515):     at android.os.Handler.handleCallback(Handler.java:587)
05-03 20:14:01.627: WARN/System.err(1515):     at android.os.Handler.dispatchMessage(Handler.java:92)
05-03 20:14:01.627: WARN/System.err(1515):     at android.os.Looper.loop(Looper.java:123)
05-03 20:14:01.627: WARN/System.err(1515):     at android.app.ActivityThread.main(ActivityThread.java:4627)
05-03 20:14:01.627: WARN/System.err(1515):     at java.lang.reflect.Method.invokeNative(Native Method)
05-03 20:14:01.627: WARN/System.err(1515):     at java.lang.reflect.Method.invoke(Method.java:521)
05-03 20:14:01.647: WARN/System.err(1515):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-03 20:14:01.647: WARN/System.err(1515):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-03 20:14:01.647: WARN/System.err(1515):     at dalvik.system.NativeStart.main(Native Method)
05-03 20:14:01.606: WARN/System.err(1515):     at android.view.View$PerformClick.run(View.java:8816)
05-03 20:14:01.616: WARN/System.err(1515):     at android.os.Handler.handleCallback(Handler.java:587)
05-03 20:14:01.627: WARN/System.err(1515):     at android.os.Handler.dispatchMessage(Handler.java:92)
05-03 20:14:01.627: WARN/System.err(1515):     at android.os.Looper.loop(Looper.java:123)
05-03 20:14:01.627: WARN/System.err(1515):     at android.app.ActivityThread.main(ActivityThread.java:4627)
05-03 20:14:01.627: WARN/System.err(1515):     at java.lang.reflect.Method.invokeNative(Native Method)
05-03 20:14:01.627: WARN/System.err(1515):     at java.lang.reflect.Method.invoke(Method.java:521)
05-03 20:14:01.647: WARN/System.err(1515):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-03 20:14:01.647: WARN/System.err(1515):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-03 20:14:01.647: WARN/System.err(1515):     at dalvik.system.NativeStart.main(Native Method)
05-03 20:14:01.627: WARN/System.err(1515):     at java.lang.reflect.Method.invoke(Method.java:521)
05-03 20:14:01.647: WARN/System.err(1515):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-03 20:14:01.647: WARN/System.err(1515):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-03 20:14:01.647: WARN/System.err(1515):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

Most often, you can get a response code by calling .getResponseCode() on your connection a second time. This was confusing for me at first, but if you read HttpURLConnectionImpl enough times your eyes will stop bleeding and see the truth...

If you modify your code in this way, you will get the response code:

try
    {
        url = new URL(urlBuilder.toString());
        conn = (HttpURLConnection) url.openConnection();
        conn.setDoInput(true);
        conn.setConnectTimeout(TIME_OUT);
        conn.setRequestMethod(METHOD_GET);
        conn.setRequestProperty("accept", "*/*");
        conn.connect();
        int responseCode = conn.getResponseCode();   //throw IOException:Received authentication challenge is null
        if (responseCode == HTTP_OK)
        {
            inStream = conn.getInputStream();
            response = getResponse(inStream);
        }
        else
        {
            response = "response code："+responseCode;
        }
    } catch (Exception e)
    {
        // Here you can get the correct response code
        if (conn != null) {
            int responseCodeAfterException = conn.getResponseCode();
            // Handle according to new response code
        }
        // Maybe don't throw e if 401?
        throw e;
    }
    finally
    {
        conn.disconnect();
    }
    return response;
}

See responseCodeAfterException.