Google GSON nested HashMaps deserialization

Question

In my current project i use GSON library in android, and i\'ve faced a problem of nested Maps deserializtion. This is how initial json looks like

 {

\"5\":         


        

Answer 1

This gson.fromJson(br, HashMap.class); tells to Gson that you want to deserialize to a Map of unknown value type. You would be tempted to specifiy something like Map<String,Category>.class, but you can not do this in Java so the solution is to use what they called TypeToken in Gson.

Map<String, Category> categoryMap = gson.fromJson(br, new TypeToken<Map<String, Category>>(){}.getType());