Getting "declares multiple JSON fields named" error when serializing with GSON

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Type type = new TypeToken<HashMap<String , MovieDb>>() {}.getType();
gson.fromJson(json, type); //ERROR HERE !!!

When I convert from Json to the hashmap object it works fine without minifying enabled. But when minify is enabled it gives me the following error at this line: 

java.lang.IllegalArgumentException: class a.a.a.a.b declares multiple JSON fields named a
        at com.google.b.b.a.i.a(ReflectiveTypeAdapterFactory.java:172)
        at com.google.b.b.a.i.a(ReflectiveTypeAdapterFactory.java:102)
        at com.google.b.e.a(Gson.java:458)
        at com.google.b.b.a.b.a(CollectionTypeAdapterFactory.java:53)
        at com.google.b.e.a(Gson.java:458)
        at com.google.b.b.a.i.a(ReflectiveTypeAdapterFactory.java:117)
        at com.google.b.b.a.i.a(ReflectiveTypeAdapterFactory.java:166)
        at com.google.b.b.a.i.a(ReflectiveTypeAdapterFactory.java:102)
        at com.google.b.e.a(Gson.java:458)
        at com.google.b.b.a.g.a(MapTypeAdapterFactory.java:126)
        at com.google.b.e.a(Gson.java:458)
        at com.google.b.e.a(Gson.java:926)
        at com.google.b.e.a(Gson.java:892)
        at com.google.b.e.a(Gson.java:841)
        at com.techy.nateshmbhat.moviego.i.onPreExecute(MovieInterface.java:180)
        at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:648)
        at android.os.AsyncTask.execute(AsyncTask.java:595)
        at com.techy.nateshmbhat.moviego.i.b(MovieInterface.java:101)
        at com.techy.nateshmbhat.moviego.a.a(Activity_InTheaterMovies.java:55)
gson android-studio android json java
2 Answers

Your error is most propably because you minify two fields to a same name a. Something like:

@SerializedName("a")
Long veryLongFieldName;

@SerializedName("a")
Long anotherVeryLongFieldName;

Note that these can be either in the same class or if using inheritance it is enough that they are in the same inheritance tree. Gson can not assign two values to one minimized field name a.

It could of course also be that you have minimized some field to a name that is already reserved by some other unminimized field.

user_64133770

I've faced this issue when I had context property/variable in the model class

user_31550820
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