Android Null Pointer Exception in Retrofit response

Question

In my application i have been using retrofit for my webservice calls. It is working fine but when application goes in to background it crashes and got the error log as,

  java.lang.NullPointerException: Attempt to invoke interface method 'void    retrofit.Callback.failure(retrofit.RetrofitError)' on a null object   reference
    at retrofit.CallbackRunnable$2.run(CallbackRunnable.java:53)
    at android.os.Handler.handleCallback(Handler.java:739)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:145)
    at android.app.ActivityThread.main(ActivityThread.java:5942)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1400)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1195)


Can anyone help me to overcome this issue..??

This is my Retrofit client class,

public class RetrofitClient {
private static RetrofitCommonService RETROFIT_CLIENT;
public RetrofitClient() {}
public static RetrofitCommonService getInstance() {
    //if REST_CLIENT is null then set-up again.
    if (RETROFIT_CLIENT == null) {
        setupRestClient();
    }
    return RETROFIT_CLIENT;
}

private static void setupRestClient() {
    RestAdapter restAdapter = new RestAdapter.Builder()
            .setClient(new OkClient(new OkHttpClient()))
            .setEndpoint(Constants.BASE_URL)
            //.setLogLevel(RestAdapter.LogLevel.FULL)
            .build();
    RETROFIT_CLIENT = restAdapter.create(RetrofitCommonService.class);
}
}

This is my Retrofit Service interface,

 public interface RetrofitCommonService {

@FormUrlEncoded
@POST("/user")
void doRegistration(@Field("user[mobile_number]") String phone, @Field("user[new_uid]") String imei,
                    Callback<RetrofitResponse> response);

 }

And this way i am making a call to Retrofit service from my activity and activity implementing retrofit callbacks.

 RetrofitCommonService mRetrofitCommonService = RetrofitClient.getInstance();
    mRetrofitCommonService.doRegistration(mPhoneNumber, getDeviceId(), this);

public class RegistrationActivity extends Activity implements Callback<RetrofitResponse>{

}

@Override
public void success(RetrofitResponse retrofitResponse, Response response) {

      }

@Override
public void failure(RetrofitError error) {
}

You provided not much more than the error message. It says that the Callback object was null. So make sure you do asynchronous calls always with a valid Callback. — Henry
– Henry, Commented Oct 16, 2015 at 5:34

Nidheesh · Accepted Answer · 2015-10-29 12:40:50Z

3

Fixed this issue.

In my activity i have two Retrofit services operations and these two services relay on same Retrofit Callback methods. And these causes null pointer when one service try to get a callback at the same time callback is used by other service. I have removed the callback methods and used return objects from Retrofit service. Then relaying on the callback method is not needed.

This worked for me...

answered Oct 29, 2015 at 12:40

Nidheesh

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1 Comment

csonuryilmaz Over a year ago

We have the same problem according to Google Play crash reports. How can we regenerate the case (situation) on development environment. Any suggested steps?

sandeep · Accepted Answer · 2017-11-10 14:50:01Z

1

Callback should be properly initialized before calling the method that invokes the callback.

answered Nov 10, 2017 at 14:50

sandeep

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