2.8.5；NullPointerException；TypeAdapterFactory

[geolo123]

java.lang.NullPointerException: Attempt to invoke interface method 'com.google.gson.TypeAdapter com.google.gson.TypeAdapterFactory.create(com.google.gson.Gson, com.google.gson.reflect.TypeToken)' on a null object reference
at com.google.gson.Gson.getAdapter(Gson.java:458)
at com.google.gson.Gson.fromJson(Gson.java:926)
at com.google.gson.Gson.fromJson(Gson.java:892)
at com.google.gson.Gson.fromJson(Gson.java:841)
at com.google.gson.Gson.fromJson(Gson.java:813)

[geolo123]

help

[Omega-Ariston]

It would be good if you can provide the context that someone else can reproduce this error from :)

[aalaprawat]

any updates on this ?

[eamonnmcmanus]

@aalaprawat if you are experiencing a similar exception, perhaps you could add some details about what you are doing when the exception occurs? What the Gson setup is and what the JSON input is that triggers the problem.

[aalaprawat]

Iam not able to replicate this issue on my device. But various devices are facing this issue across various android api levels in production app.

Fatal Exception: java.lang.NullPointerException: Attempt to invoke interface method 'com.google.gson.TypeAdapter com.google.gson.TypeAdapterFactory.create(com.google.gson.Gson, com.google.gson.reflect.TypeToken)' on a null object reference at com.google.gson.Gson.getAdapter(Gson.java:458) at com.google.gson.Gson.toJson(Gson.java:696) at com.google.gson.Gson.toJson(Gson.java:683) at com.google.gson.Gson.toJson(Gson.java:638) at com.google.gson.Gson.toJson(Gson.java:618) at in.workindia.nileshdungarwal.helpers.JsonHelper.convertJobContentsToJson(JsonHelper.java:322) at in.workindia.nileshdungarwal.data_parser.ContentValuesParser.parseJobs(ContentValuesParser.java:335) at in.workindia.nileshdungarwal.data_parser.ContentValuesParser.parseNewJobs(ContentValuesParser.java:70) at in.workindia.nileshdungarwal.retrofit.RetrofitSyncAll.finalProcessOfJobs(RetrofitSyncAll.java:844) at in.workindia.nileshdungarwal.retrofit.RetrofitSyncAll$101.onResponse(RetrofitSyncAll.java:6591) at retrofit2.DefaultCallAdapterFactory$ExecutorCallbackCall$1.lambda$onResponse$0(DefaultCallAdapterFactory.java:81) at retrofit2.DefaultCallAdapterFactory$ExecutorCallbackCall$1.lambda$onResponse$0$DefaultCallAdapterFactory$ExecutorCallbackCall$1(DefaultCallAdapterFactory.java:3) at retrofit2.-$$Lambda$DefaultCallAdapterFactory$ExecutorCallbackCall$1$hVGjmafRi6VitDIrPNdoFizVAdk.run(-.java:3) at android.os.Handler.handleCallback(Handler.java:938) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:246) at android.app.ActivityThread.main(ActivityThread.java:8595) at java.lang.reflect.Method.invoke(Method.java) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130)

[Marcono1234]

Unfortunately Gson does not check for null for the GsonBuilder.registerTypeAdapterFactory method. Could you please check whether by accident you are calling it with null as value?

[aalaprawat]

@Marcono1234

gsonBuilder = new GsonBuilder(); gsonBuilder.registerTypeAdapter(JsonNode.class, new JsonNodeSerializer()); gsonBuilder.registerTypeAdapter(JsonNode.class, new JsonNodeDeserializer()); Gson gson = gsonBuilder.create();

I don't think this could be null

[Marcono1234]

@aalaprawat, were you able to reproduce this locally with a debug build of your application as well? Could you please try to create a small self-contained sample project using the latest Gson version which shows this issue?

[aalaprawat]

Currently, I am using Gson 2.8.6, would upgrading resolve the issue?
@Marcono1234

[Marcono1234]

I am afraid using the latest version most likely does not make a big difference, but in case this is really a Gson bug it would avoid having to track down bugs in an old Gson version. Future Gson versions will also add validation for the GsonBuilder methods (#2179), maybe that would help track down the bug.

The stack trace suggests that somehow null was added as element to the Gson.factories list; but I don't see how that could have happened, other than by a call to GsonBuilder.registerTypeAdapterFactory(null).

Since you mentioned it only occurs on some devices, maybe there is something wrong with those devices, or the Android version they are running.

[aalaprawat]

facing issues across all the devices and API versions, As mentioned above through code snippet, I can't point where GsonBuilder.registerTypeAdapterFactory(null) could happen

[Marcono1234]

Are you still experiencing this with the latest Gson version (currently 2.10.1)? It includes the null checks for GsonBuilder.registerTypeAdapterFactor; maybe that allows tracking down the issue.

[Marcono1234]

I am going to close this because no answer has been provided. If you still experience this with the latest Gson version, feel free to comment here again with more details.