REInVent650 commented 2 years ago

Gson version

2.9.0 and 2.8.7

Java / Android version

Android 11 & 12 Java 8

Used tools

Gradle version: 7.1.2
compileSdk 32
buildToolsVersion '32.0.0'
com.google.gms:google-services:4.3.10

Description

NullPointerException when trying to add a HashMap to an ArrayList that Gson has initialized with or without data from a json file.

Expected behavior

A HashMap to be added to the ArrayList

Actual behavior

A NullPointerException occured indicating the ArrayList was either null or not of the expected type on Android 11 and 12. Android 10 and below A HashMap is succesfully added to the ArrayList that Gson initialized.

Reproduction steps

Make sure you are using android 11 or 12

ArrayList<HashMap<String, String>> logData;
logData = new Gson().fromJson(filePath, new TypeToken<ArrayList<HashMap<String, String>>>() {}.getType());

Make a new HashMap add it to the ArrayList that Gson has initialized

HashMap<String, String> map = new HashMap<>();
map.put("key1", "value1");
map.put("key2", "value2");
logData.add(map);

Exception stack trace

 java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.util.ArrayList.add(java.lang.Object)' on a null object reference
        at com.mvp.shakeit.ForegroundService.logJson(ForegroundService.java:204)
        at com.mvp.shakeit.ForegroundService.levelTwoWipe(ForegroundService.java:221)
        at com.mvp.shakeit.ForegroundService.lambda$runTask$0$com-mvp-shakeit-ForegroundService(ForegroundService.java:142)
        at com.mvp.shakeit.ForegroundService$$ExternalSyntheticLambda0.onTranslation(Unknown Source:5)
        at com.mvp.shakeit.AccelUtil$1.onSensorChanged(AccelUtil.java:50)
        at android.hardware.SystemSensorManager$SensorEventQueue.dispatchSensorEvent(SystemSensorManager.java:886)
        at android.os.MessageQueue.nativePollOnce(Native Method)
        at android.os.MessageQueue.next(MessageQueue.java:335)
        at android.os.Looper.loopOnce(Looper.java:161)
        at android.os.Looper.loop(Looper.java:288)
        at android.app.ActivityThread.main(ActivityThread.java:7870)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1019)

I will try and put a MRPE together tomorrow

REInVent650 commented 2 years ago

I did find a workaround for some Android 11 devices, by making this empty class.

public class MyType extends ArrayList<HashMap<String, String>> {
}

then when using from Json I pass it in as the type.

logData = new Gson().fromJson(filePath, MyType.class);

eamonnmcmanus commented 2 years ago

Are you using ProGuard or another code-shrinking solution? Can you say whether the same problem occurs when you don't?

luiges90 commented 1 year ago

Sorry for necro'ing, but we believe that we have also hit a similar issue.

It happens on all Android 11, 12, 13
Only happens when targeting Android 12. (No issue if targets Android 11)
Only happens when migrating from targeting Android 11 apps to targeting Android 12 apps.
- i.e. Objects created when build targets Android 12 have no issue.
Only happens when Proguard (R8) is enabled AND debuggable flag is false, throughout all builds
- i.e. Objects created in un-proguarded builds and loaded from proguarded builds have no issue.
Happens on Gson 2.8.9, 2.9.1 and 2.10
Our code tries to deserialize a map rather than a list however, and got a different exception

code (Kotlin):

val sessions = gson.fromJson<MutableMap<Int, Triple<UserModel?, Token?, Boolean?>>>(
            sessionsStr,
            object : TypeToken<MutableMap<Int, Triple<UserModel, Token, Boolean>>>() {}.type)

exception:

2022-12-06 10:09:33.591 11381-11381/? W/System.err: ka.w: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BOOLEAN at line 1 column 827 path $..c
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at na.n$a.read(ReflectiveTypeAdapterFactory.java:14)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at na.m.b(ReflectiveTypeAdapterFactory.java:1)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at na.n$c.c(Unknown Source:0)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at na.n$a.read(ReflectiveTypeAdapterFactory.java:9)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at na.q.read(Unknown Source:2)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at na.h$a.read(MapTypeAdapterFactory.java:21)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at ka.i.b(Gson.java:5)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at ka.i.e(Gson.java:4)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at ka.i.d(Unknown Source:4)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at df.y0.invoke(RootInteractor.kt:39)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at bf.b.accept(R8$$SyntheticClass:71)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at io.reactivex.internal.observers.s.onNext(LambdaObserver.java:2)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at io.reactivex.internal.operators.observable.q2$a.run(ObservableObserveOn.java:23)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at io.reactivex.android.schedulers.b$b.run(HandlerScheduler.java:1)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at android.os.Handler.handleCallback(Handler.java:942)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:99)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at android.os.Looper.loopOnce(Looper.java:201)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at android.os.Looper.loop(Looper.java:288)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:7898)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:936)
2022-12-06 10:09:33.591 11381-11381/? W/System.err: Caused by: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BOOLEAN at line 1 column 827 path $..c
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at com.google.gson.stream.JsonReader.beginObject(JsonReader.java:7)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     at na.n$a.read(ReflectiveTypeAdapterFactory.java:4)
2022-12-06 10:09:33.591 11381-11381/? W/System.err:     ... 21 more

Marcono1234 commented 1 year ago

@luiges90, personally I would treat that as separate issue initially because the stack traces are so different. Could you please create a separate issue for this?

Also, could you please make sure you have configured ProGuard / R8 correctly so it does not obfuscate the field names of your classes. Maybe also try using GsonBuilder.addReflectionAccessFilter(ReflectionAccessFilter.BLOCK_ALL_PLATFORM) (requires Gson 2.9.1 or newer) to be sure you don't serialize any Android classes by accident.

Though might be good to further discuss this in a separate GitHub issue.

google / gson

ArrayList initialized by Gson with a TypeToken returns NullPointerException on android 11 & 12 #2097