How to generate random UUID in Java
What is UUID?
The full form of UUID is Universally Unique Identifier. A UUID represents a 128-bit value that is unique. The standard representation of UUID uses hex digits.
For example:
3c0969ac-c6e3-40f2-9fc8-2a59b8987918
cb7125cc-d78a-4442-b21b-96ce9227ef51
UUID in Java
The UUID class in the java.util package bundles the method to generate random UUID.
There are four different versions of UUID. They are as follows:
- Time-based UUID
- DCE security UUID
- Name-based UUID
- Randomly generated UUID
This shot covers how to generate a randomly generated UUID.
Randomly generated UUID
The randomly generated UUID uses a random number as the source to generate the UUID.
In Java, the randomUUID() static method is used to generate a random UUID. The method internally uses SecureRandom class, which provides a cryptographically strong random number generator.
Every UUID is associated with a version number. The version number describes how the UUID was generated. The .version() method is used to get the version of the generated UUID.
| Version number in java | How the UUID was generated |
|---|---|
| 1 | Time-based UUID |
| 2 | DCE security UUID |
| 3 | Name-based UUID |
| 4 | Randomly generated UUID |
import java.util.UUID;public class GenUUID {public static void main(String[] args) {UUID uuid = UUID.randomUUID();System.out.println("UUID generated - " + uuid);System.out.println("UUID Version - " + uuid.version());}}
