How to generate a checksum for an java object

Question

I\'m looking for a solution to generate a checksum for any type of Java object, which remains the same for every execution of an application that produces the same object.

Answer 1

1. Object -> String (For example, GSON - you will not have to write serialization not to list all fields of your class)

2. String.hashCode() -> int (Instead of Object.hashCode()! This realization of hashCode() depends on content of String, not on address in memory --- you can use it across different app launches, different threads, etc.)

(or 2. String -> md5)