How an object can be updated?

Android
1

When I try to update an object using save method Backendless doesn’t update this object it creates a new one.

2

3.0.11

3

I mean language: Android, JS… ?

4

Android SDK

5

Make sure that class contains getters and setters for all fields, and no-argument constructor.
If it doesn’t - provide please a small code snippet reprodicing the problem and your class.