UndeliverableException with RxJava2 and Retrofit

[Ashutosh7]

There is an exception that is repeatedly showing up on Crashlytics(Fabric) for my app. I use rxjava2 with retrofit to make my http calls.

This is all that is there in the logs on crashlytics(below). Would be grateful for any help /insights.

The cause of the issue seems to be the retrofit library.

Fatal Exception: io.reactivex.exceptions.UndeliverableException: retrofit2.adapter.rxjava2.HttpException: HTTP 404 at io.reactivex.plugins.RxJavaPlugins.onError(RxJavaPlugins.java:349) at io.reactivex.internal.operators.single.SingleZipArray$ZipCoordinator.innerError(SingleZipArray.java:141) at io.reactivex.internal.operators.single.SingleZipArray$ZipSingleObserver.onError(SingleZipArray.java:177) at io.reactivex.internal.operators.single.SingleDoOnError$DoOnError.onError(SingleDoOnError.java:63) at io.reactivex.internal.operators.single.SingleDoOnSuccess$DoOnSuccess.onError(SingleDoOnSuccess.java:64) at io.reactivex.internal.operators.single.SingleSubscribeOn$SubscribeOnObserver.onError(SingleSubscribeOn.java:73) at io.reactivex.internal.operators.observable.ObservableSingleSingle$SingleElementObserver.onError(ObservableSingleSingle.java:95) at retrofit2.adapter.rxjava2.BodyObservable$BodyObserver.onNext(BodyObservable.java:56) at retrofit2.adapter.rxjava2.BodyObservable$BodyObserver.onNext(BodyObservable.java:37) at retrofit2.adapter.rxjava2.CallExecuteObservable.subscribeActual(CallExecuteObservable.java:43) at io.reactivex.Observable.subscribe(Observable.java:10842) at retrofit2.adapter.rxjava2.BodyObservable.subscribeActual(BodyObservable.java:34) at io.reactivex.Observable.subscribe(Observable.java:10842) at io.reactivex.internal.operators.observable.ObservableSingleSingle.subscribeActual(ObservableSingleSingle.java:35) at io.reactivex.Single.subscribe(Single.java:2703) at io.reactivex.internal.operators.single.SingleSubscribeOn$SubscribeOnObserver.run(SingleSubscribeOn.java:89) at io.reactivex.Scheduler$DisposeTask.run(Scheduler.java:452) at io.reactivex.internal.schedulers.ScheduledRunnable.run(ScheduledRunnable.java:61) at io.reactivex.internal.schedulers.ScheduledRunnable.call(ScheduledRunnable.java:52) at java.util.concurrent.FutureTask.run(FutureTask.java:237) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:152) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:265) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) at java.lang.Thread.run(Thread.java:818) Caused by retrofit2.adapter.rxjava2.HttpException: HTTP 404 at retrofit2.adapter.rxjava2.BodyObservable$BodyObserver.onNext(BodyObservable.java:54) at retrofit2.adapter.rxjava2.BodyObservable$BodyObserver.onNext(BodyObservable.java:37) at retrofit2.adapter.rxjava2.CallExecuteObservable.subscribeActual(CallExecuteObservable.java:43) at io.reactivex.Observable.subscribe(Observable.java:10842) at retrofit2.adapter.rxjava2.BodyObservable.subscribeActual(BodyObservable.java:34) at io.reactivex.Observable.subscribe(Observable.java:10842) at io.reactivex.internal.operators.observable.ObservableSingleSingle.subscribeActual(ObservableSingleSingle.java:35) at io.reactivex.Single.subscribe(Single.java:2703) at io.reactivex.internal.operators.single.SingleSubscribeOn$SubscribeOnObserver.run(SingleSubscribeOn.java:89) at io.reactivex.Scheduler$DisposeTask.run(Scheduler.java:452) at io.reactivex.internal.schedulers.ScheduledRunnable.run(ScheduledRunnable.java:61) at io.reactivex.internal.schedulers.ScheduledRunnable.call(ScheduledRunnable.java:52) at java.util.concurrent.FutureTask.run(FutureTask.java:237) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:152) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:265) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) at java.lang.Thread.run(Thread.java:818)

[JakeWharton]

Looks like you're zipping multiple streams and more than one has errored. After the first one RxJava has nowhere to send the error except to the RxJavaPlugins which then delivers it to the thread uncaught exception handler.

This isn't a problem with Retrofit.