How to Generate UUIDs as Primary Keys using Hibernate, A step-by-step Guide!

  • Cubettech
  • Java
  • 2 years ago
How to Generate UUIDs as Primary Keys using Hibernate, A step-by-step Guide!

UUID (Universally Unique Identifier) is an alphanumeric string that can be used to identify a resource independently and universally. UUIDs are widely used for computer software applications, databases, and storage systems to identify digital objects with a high likelihood of uniqueness. 

In this article, we will see how we can use Hibernate as an ORM layer with the help of byte streams to generate UUIDs as primary keys in our application.

What is UUID?

A UUID is a type of unique identifier that is generated by specific services and systems such as databases, virtual machines, operating systems, and applications. UUID allows special software called ‘fuzzers’ to test the resiliency of defenses because it is easy to generate billions of random UUIDs that do not overlap.

There are many applications where you can use UUID, such as:

  1. ERP, CRM, and other software that uses connections between different data sources.
  2. In web services, mobile apps, or any applications that query from a database.
  3. In web services to identify assets or entities in APIs.
  4. When we need to give a unique name for files, images, etc.
  5. UUIDs are used in many applications and technologies, such as Linux Distributed File System (DFS), Microsoft Active Directory, and Network Virtual Server (NVS). 
  6. In addition, they can be used when creating identifiers for digital objects such as UML sequence numbers and XML file IDs.

Benefits of using UUIDs

UUIDs are widely used for several reasons. They’re a globally unique identifier that’s completely independent of any organization or network. 

  • It is ideal for applications that need to be scalable and highly available. UUIDs can also be very useful when you have large volumes of data. 
  • They enable you to keep track of items with greater precision and accuracy.
  • Another benefit of UUIDs is that they’re easy to remember. Anyone who has used them will understand how to use them immediately. It makes UUIDs very convenient for users.
  • Finally, UUIDs are much more secure than other types of identifiers. This is because they’re virtually impossible to spoof or replicate.

How to use UUID?

UUIDs (universally unique identifiers) are short strings of digits guaranteed to be unique on a given system. Because UUIDs never change, they can be used as the reliable “fetch me out of here” for any kind of data. In a nutshell, a UUID is like a digital fingerprint for your data.

There are two main ways to use UUIDs:

  • Create a new UUID from scratch. If you’re creating a new UUID, it is advised to start with an incrementing number (e.g., 1, 2, 3, etc.), which will simplify future uses.
  • Compare existing UUIDs to see if they match. If you have two or more data objects that have the same UUID, they must be identical and should be treated as such by applications and services.

Steps for Generating UUIDs using Java

Generating UUIDs is simple in Java. It’s just four lines of code. To create a UUID, you must start with an integer value followed by a letter and then another integer. It can be anything between 0 and 4,294,967,295. You must also include an optional prefix and suffix.

The JDK has a few built-in methods that use UUIDs to generate unique IDs like this:


This returns a String that looks something like “546FDF23-E1EC-4F8B-B6E4-D36CBE11BFD0.”

But the values returned by these methods will only look random for short periods. At some point in the future, two computers that both have Python installed on them will generate the same UUID value. So it’s essential to store your UUIDs in a database or file, so they don’t get lost.


To generate UUIDs as a primary key in your application, you can use the UUID generator provided by Hibernate. This can be configured directly in your application’s mapping file or library. The UUID generator ignores any data that falls outside your specified range. This ensures that every UUID generated is unique.

You can also use the UUID generator in your HQL or JPQL queries. The UUID generator can also be used in prepared statements.

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