A class created by Brian Nettleton that allows to transform a JSON string to a Map object for GSON. To use it, just register a new Type Adapter for Object.class.

GenericObjectDeserializer.java

/**
 * @author Brian Nettleton
 */
class GenericObjectDeserializer implements JsonDeserializer<Object>
{

    @Override
    public Object deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException
    {
        if( json.isJsonNull() ) {
            return null;
        }
        else if ( json.isJsonPrimitive() ) {
            JsonPrimitive primitive = json.getAsJsonPrimitive();
            if ( primitive.isString() ) {
                return primitive.getAsString();
            }
            else if ( primitive.isNumber() ) {
                return primitive.getAsNumber();
            }
            else if ( primitive.isBoolean() ) {
                return primitive.getAsBoolean();
            }
        }
        else if ( json.isJsonArray() ) {
            JsonArray array = json.getAsJsonArray();
            List<Object> result = new ArrayList<Object>(array.size());
            /* Object[] result = new Object[array.size()]; */
            int i = 0;
            for( JsonElement element : array ) {
                /* result[i] = deserialize(element, null, context); */
                result.set(i, deserialize(element, null, context));
                ++i;
            }
            return result;
        }
        else if ( json.isJsonObject() ) {
            JsonObject object = json.getAsJsonObject();
            Map<String, Object> result = new HashMap<String,Object>();
            for( Map.Entry<String, JsonElement> entry : object.entrySet() ) {
                Object value = deserialize(entry.getValue(), null, context);
                result.put(entry.getKey(), value);
            }
            return result;
        }
        else {
            throw new JsonParseException("Unknown JSON type for JsonElement " + json.toString());
        }
        return null;
    }
    
}