> For the complete documentation index, see [llms.txt](https://docs.ovaledge.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ovaledge.com/release8.3/deployment-and-maintenance/upgrade/java21-upgrade-linux.md).

# Java21 Upgrade (Linux)

This article describes the steps to upgrade Java to version 21 on a Linux machine. It outlines the installation process, configuration updates, and validation steps required to ensure the system uses the correct Java version. The procedure follows a structured approach aligned with standard deployment practices.

## Prerequisites

* Linux-based system with root or sudo access
* Access to a package manager (e.g., yum)
* Existing Java installation on the system
* Terminal or command-line access

## Steps Involved

### Verify Existing Java Version

* Run the following command to check the currently installed Java version:

  ```
  java -version
  ```

  \
  Sample Reference Screenshot:

  <figure><img src="https://content.gitbook.com/content/8fgltewNgYZ8ucAp7Svt/blobs/WiB3JLDkeveTl0QJMp73/unknown.png" alt=""><figcaption></figcaption></figure>

### Install Java 21

* Execute the following command to install Java 21:

  ```
  sudo yum install java-21-openjdk-devel -y
  ```

  \
  Sample Reference Screenshot:

  <figure><img src="https://content.gitbook.com/content/8fgltewNgYZ8ucAp7Svt/blobs/nuB9RRjvEaRDdXty9kuk/unknown.png" alt=""><figcaption></figcaption></figure>

### Configure Java Alternatives

* Run the following command to list and configure available Java versions:&#x20;

  ```
  sudo update-alternatives --config java
  ```
* From the displayed list, select Java 21 by entering the corresponding number, then press Enter.\
  \
  Sample Reference Screenshot:

  <figure><img src="https://content.gitbook.com/content/8fgltewNgYZ8ucAp7Svt/blobs/qlAFcnIzYxkMJqly6vS3/unknown.png" alt=""><figcaption></figcaption></figure>

### Validate Java Upgrade

* Verify that the system is using Java 21 by running:

  ```
  java -version
  ```

  \
  Sample Reference Screenshot:

  <figure><img src="https://content.gitbook.com/content/8fgltewNgYZ8ucAp7Svt/blobs/Ao8APDUboGKwZEkHoEbr/unknown.png" alt=""><figcaption></figcaption></figure>

***

Copyright © 2026, OvalEdge LLC, Peachtree Corners, GA, USA.


---

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