Gson: Safe long deserialization

JsonLongDeserializer.java

public class JsonLongDeserializer implements JsonDeserializer<Long> {
    @Override
    public Long deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) {
        try {
            return json.getAsLong();
        } catch (NumberFormatException e) {
            return -1L;
        }
    }
}

// To register:
new GsonBuilder().registerTypeAdapter(long.class, new JsonLongDeserializer()).create();