Crash on loading serialized object from intent in To-Many case

hi, the issue is, I have a Receipt class with an arraylist of items. so I used ToMany relation and changed arraylist to To-Many and in ReceiptItem class created a new field with To-One relationship. Its working fine and saving in 2 tables properly.

@Entity
public class Receipt implements Serializable {
    public ToMany<ReceiptItem> receipt_items;
   .... 
}
@Entity
public class ReceiptItem implements Serializable {
    public ToOne<Receipt> receiptToOne;
}

I am sending my receipt object from one activity to another activity by serialization and getting in another activity.
receipt = (Receipt) (intent.getSerializableExtra("key_receiptobject"));

No issues and this is working fine.

Now for proper One-To-Many relationship I added, @Backlink annotation.

@Entity
public class Receipt implements Serializable {
    @Backlink
    public ToMany<ReceiptItem> receipt_items;
   .... 
}

and my app crashes on this line,
receipt = (Receipt) (intent.getSerializableExtra("key_receiptobject"));

Can you please help me to resolve this.

Issue Basics

• ObjectBox version : 1.4.0
• Reproducibility: always

Logs & stackstraces

E/UncaughtException: java.lang.RuntimeException: Unable to start activity ComponentInfo{}: java.lang.RuntimeException: Parcelable encountered ClassNotFoundException reading a Serializable object (name = abc.sales.entity.Receipt)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2429)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2493)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1357)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5459)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
Caused by: java.lang.RuntimeException: Parcelable encountered ClassNotFoundException reading a Serializable object (name = abc.sales.entity.Receipt)
at android.os.Parcel.readSerializable(Parcel.java:2512)
at android.os.Parcel.readValue(Parcel.java:2315)
at android.os.Parcel.readArrayMapInternal(Parcel.java:2614)
at android.os.BaseBundle.unparcel(BaseBundle.java:221)
at android.os.BaseBundle.getSerializable(BaseBundle.java:992)
at android.os.Bundle.getSerializable(Bundle.java:880)
at android.content.Intent.getSerializableExtra(Intent.java:5468)
at abc.sales.Activities.sale.ITPrintReceiptActivity.onCreate(ITPrintReceiptActivity.java:129)
at android.app.Activity.performCreate(Activity.java:6259)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1130)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2382)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2493) 
at android.app.ActivityThread.-wrap11(ActivityThread.java) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1357) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5459) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 
Caused by: java.lang.ClassNotFoundException: long
at java.lang.Class.classForName(Native Method)
at java.lang.Class.forName(Class.java:324)
at android.os.Parcel$2.resolveClass(Parcel.java:2498)
at java.io.ObjectInputStream.readNewClassDesc(ObjectInputStream.java:1641)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:657)
at java.io.ObjectInputStream.readNewClass(ObjectInputStream.java:1512)
at java.io.ObjectInputStream.readNonPrimitiveContent(ObjectInputStream.java:755)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:1983)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:1940)
at java.io.ObjectInputStream.readFieldValues(ObjectInputStream.java:1113)
at java.io.ObjectInputStream.defaultReadObject(ObjectInputStream.java:454)
at java.io.ObjectInputStream.readObjectForClass(ObjectInputStream.java:1345)
at java.io.ObjectInputStream.readHierarchy(ObjectInputStream.java:1242)
at java.io.ObjectInputStream.readNewObject(ObjectInputStream.java:1835)
at java.io.ObjectInputStream.readNonPrimitiveContent(ObjectInputStream.java:761)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:1983)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:1940)
at java.io.ObjectInputStream.readFieldValues(ObjectInputStream.java:1113)
at java.io.ObjectInputStream.defaultReadObject(ObjectInputStream.java:454)
at java.io.ObjectInputStream.readObjectForClass(ObjectInputStream.java:1345)
at java.io.ObjectInputStream.readHierarchy(ObjectInputStream.java:1242)
at java.io.ObjectInputStream.readNewObject(ObjectInputStream.java:1835)
at java.io.ObjectInputStream.readNonPrimitiveContent(ObjectInputStream.java:761)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:1983)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:1940)
at java.io.ObjectInputStream.readFieldValues(ObjectInputStream.java:1113)
at java.io.ObjectInputStream.defaultReadObject(ObjectInputStream.java:454)
at java.io.ObjectInputStream.readObjectForClass(ObjectInputStream.java:1345)
at java.io.ObjectInputStream.readHierarchy(ObjectInputStream.java:1242)
at java.io.ObjectInputStream.readNewObject(ObjectInputStream.java:1835)
at java.io.Obje
01-19 22:58:22.752 7470-7488/abc.sales D/FA: Logging event (FE): _ae, Bundle[{_o=crash, timestamp=1516382902748, fatal=1}]
01-19 22:58:23.008 7470-7470/abc.sales E/AndroidRuntime: FATAL EXCEPTION: main
Process: abc.sales, PID: 7470
java.lang.RuntimeException: Unable to start activity ComponentInfo{abc.sales/abc.sales.Activities.sale.ITPrintReceiptActivity}: java.lang.RuntimeException: Parcelable encountered ClassNotFoundException reading a Serializable object (name = abc.sales.entity.Receipt)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2429)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2493)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1357)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5459)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
Caused by: java.lang.RuntimeException: Parcelable encountered ClassNotFoundException reading a Serializable object (name = abc.sales.entity.Receipt)
at android.os.Parcel.readSerializable(Parcel.java:2512)
at android.os.Parcel.readValue(Parcel.java:2315)
at android.os.Parcel.readArrayMapInternal(Parcel.java:2614)
at android.os.BaseBundle.unparcel(BaseBundle.java:221)
at android.os.BaseBundle.getSerializable(BaseBundle.java:992)
at android.os.Bundle.getSerializable(Bundle.java:880)
at android.content.Intent.getSerializableExtra(Intent.java:5468)
at abc.sales.Activities.sale.ITPrintReceiptActivity.onCreate(ITPrintReceiptActivity.java:129)
at android.app.Activity.performCreate(Activity.java:6259)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1130)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2382)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2493) 
at android.app.ActivityThread.-wrap11(ActivityThread.java) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1357) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5459) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 
Caused by: java.lang.ClassNotFoundException: long
at java.lang.Class.classForName(Native Method)
at java.lang.Class.forName(Class.java:324)
at android.os.Parcel$2.resolveClass(Parcel.java:2498)
at java.io.ObjectInputStream.readNewClassDesc(ObjectInputStream.java:1641)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:657)
at java.io.ObjectInputStream.readNewClass(ObjectInputStream.java:1512)
at java.io.ObjectInputStream.readNonPrimitiveContent(ObjectInputStream.java:755)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:1983)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:1940)
at java.io.ObjectInputStream.readFieldValues(ObjectInputStream.java:1113)
at java.io.ObjectInputStream.defaultReadObject(ObjectInputStream.java:454)
at java.io.ObjectInputStream.readObjectForClass(ObjectInputStream.java:1345)
at java.io.ObjectInputStream.readHierarchy(ObjectInputStream.java:1242)
at java.io.ObjectInputStream.readNewObject(ObjectInputStream.java:1835)
at java.io.ObjectInputStream.readNonPrimitiveContent(ObjectInputStream.java:761)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:1983)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:1940)
at java.io.ObjectInputStream.readFieldValues(ObjectInputStream.java:1113)
at java.io.ObjectInputStream.defaultReadObject(ObjectInputStream.java:454)
at java.io.ObjectInputStream.readObjectForClass(ObjectInputStream.java:1345)
at java.io.ObjectInputStream.readHierarchy(ObjectInputStream.java:1242)
at java.io.ObjectInputStream.readNewObject(ObjectInputStream.java:1835)
at java.io.ObjectInputStream.readNonPrimitiveContent(ObjectInputStream.java:761)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:1983)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:1940)
at java.io.ObjectInputStream.readFieldValues(ObjectInputStream.java:1113)
at java.io.ObjectInputStream.defaultReadObject(ObjectInputStream.java:454)
at java.io.ObjectInputStream.readObjectForClass(ObjectInputStream.java:1345)
at java.io.ObjectInputStream.readHierarchy(ObjectInputStream.java:1242)
at java.io.ObjectInputStream.readN

从 ITPrintReceiptActivity.java:129 开始，检查 issue 中显示的 Receipt 和 ReceiptItem 声明，比较添加 @Backlink 前后的序列化情况。使用 ObjectBox 1.4.0 和提供的 stack trace 重现 Intent 反序列化失败。完成的标准是 activity 能够在关系存在的情况下加载序列化的 Receipt，且不会出现 ClassNotFoundException。