Firebase Database Android Crash

 at libcore.reflect.ListOfTypes.getResolvedTypes(ListOfTypes.java:55)
        at libcore.reflect.ParameterizedTypeImpl.getResolvedType(ParameterizedTypeImpl.java:75)
        at libcore.reflect.ListOfTypes.resolveTypes(ListOfTypes.java:70)
        at libcore.reflect.ListOfTypes.getResolvedTypes(ListOfTypes.java:55)
        at libcore.reflect.Types.getTypeArray(Types.java:50)
        at java.lang.reflect.Method.getGenericParameterTypes(Method.java:247)
        at com.google.android.gms.internal.firebase_database.zzku.zza()
        at com.google.android.gms.internal.firebase_database.zzkt.zzb()
        at com.google.android.gms.internal.firebase_database.zzkt.zza()
        at Aux.aUx.Aux.AUx.V.public()
        at Aux.AUx.aux.AUx.B.onDataChange(:163)
        at com.google.android.gms.internal.firebase_database.zzfc.zza()
        at com.google.android.gms.internal.firebase_database.zzgx.zzdr()
        at com.google.android.gms.internal.firebase_database.zzhd.run()
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5373)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:947)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:742)
     Caused by: java.lang.ClassNotFoundException: com.walhalla.models.Result
        at java.lang.Class.classForName(Native Method)
        at java.lang.Class.forName(Class.java:309)
        at libcore.reflect.ParameterizedTypeImpl.getRawType(ParameterizedTypeImpl.java:65)
        at libcore.reflect.ParameterizedTypeImpl.getResolvedType(ParameterizedTypeImpl.java:76)
        at libcore.reflect.ListOfTypes.resolveTypes(ListOfTypes.java:70)
        at libcore.reflect.ListOfTypes.getResolvedTypes(ListOfTypes.java:55)
        at libcore.reflect.ParameterizedTypeImpl.getResolvedType(ParameterizedTypeImpl.java:75)
        at libcore.reflect.ListOfTypes.resolveTypes(ListOfTypes.java:70)
        at libcore.reflect.ListOfTypes.getResolvedTypes(ListOfTypes.java:55)
        at libcore.reflect.Types.getTypeArray(Types.java:50)
        at java.lang.reflect.Method.getGenericParameterTypes(Method.java:247)
        at com.google.android.gms.internal.firebase_database.zzku.zza()
        at com.google.android.gms.internal.firebase_database.zzkt.zzb()
        at com.google.android.gms.internal.firebase_database.zzkt.zza()
        at Aux.aUx.Aux.AUx.V.public()
        at Aux.AUx.aux.AUx.B.onDataChange(:163)
        at com.google.android.gms.internal.firebase_database.zzfc.zza()
        at com.google.android.gms.internal.firebase_database.zzgx.zzdr()
        at com.google.android.gms.internal.firebase_database.zzhd.run()
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5373)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:947)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:742)
     Caused by: java.lang.ClassNotFoundException: Didn't find class


proguard-rules.pro 

# Firebase database# Add this global rule-keepattributes Signature

# This rule will properly ProGuard all the model classes in# the package com.yourcompany.models. Modify to fit the structure# of your app.-keepclassmembers class com.yourpackagename.models.** {
  *;}

-keep class com.yourpackagename.models.** {*;} #<----   keep firebase/pojo/model class