Installing or Updating Java

Installing Java is a critical first step to using or developing plugins for Paper, Velocity, and Waterfall. This guide will walk you through the recommended installation steps for most major platforms.

Do not use headless variants of Java!

There are headless variants of Java which usually have a suffix of -headless in their package name. Those variants miss required dependencies for Paper. Therefore, using them is not recommended.

tip

This guide focuses on Amazon's Corretto OpenJDK distribution. This is because it offers the best installation experience on the most platforms. Corretto is, however, not the only OpenJDK vendor to choose from. Many alternatives exist such as Eclipse Adoptium, Microsoft and Azul Zulu. Note that the JDK Oracle distributes, while functionally identical, is not recommended due to an extremely unfriendly installer and previous hostile licensing.

Linux

Ubuntu/Debian

Installing Java 21 on Debian-based Linux distributions is very simple. First, ensure your system has all required tools to successfully install Java.

sudo apt-get update && sudo apt-get upgrade
sudo apt-get install ca-certificates apt-transport-https gnupg wget

Second, import the Amazon Corretto public key and apt repository.

wget -O - https://apt.corretto.aws/corretto.key | sudo gpg --dearmor -o /usr/share/keyrings/corretto-keyring.gpg && \
echo "deb [signed-by=/usr/share/keyrings/corretto-keyring.gpg] https://apt.corretto.aws stable main" | sudo tee /etc/apt/sources.list.d/corretto.list

Then, install Java 21 and other dependencies using the following command:

sudo apt-get update
sudo apt-get install -y java-21-amazon-corretto-jdk libxi6 libxtst6 libxrender1

Proceed to verify your installation.

RPM-based

To install Java 21 on CentOS, RHEL, Fedora, openSUSE, SLES, or any other RPM-based Linux distribution, execute the following commands depending on your package manager. Once you have finished, precede to verify your installation.

DNF

DNF is used on Fedora, CentOS/RHEL 7+, and related distributions.

sudo rpm --import https://yum.corretto.aws/corretto.key
sudo curl -Lo /etc/yum.repos.d/corretto.repo https://yum.corretto.aws/corretto.repo
sudo dnf -y install java-21-amazon-corretto-devel

Zypper

Zypper is used on openSUSE, SLES, and related distributions.

sudo zypper addrepo https://yum.corretto.aws/corretto.repo
sudo zypper refresh
sudo zypper install java-21-amazon-corretto-devel

YUM

YUM is used on older releases of CentOS/RHEL, and excessively old releases of Fedora.

sudo rpm --import https://yum.corretto.aws/corretto.key
sudo curl -Lo /etc/yum.repos.d/corretto.repo https://yum.corretto.aws/corretto.repo
sudo yum -y install java-21-amazon-corretto-devel

Windows 10 & 11

If you're on Windows 10 or 11, installing Java is just like installing any other program. Download the Amazon Corretto installer from their website.

Once you have run the installer, it is safe to click "next" through the whole process. No additional bloatware or toolbars will be installed, and all the required features are enabled out of the box.

Now, open a command prompt and precede to verify your installation.

macOS/OS X

If you're on macOS, the best way to manage Java installations is with a tool called Homebrew. Follow the instructions on their homepage to install it. Then, in your terminal run the following command:

brew install openjdk@21

Once this command has completed, continue to verify your installation.

Pterodactyl

note

On Pterodactyl versions lower than 1.2.0, an administrator account is required to change the Java version. These instructions will not apply.

If you have started a Paper server with an incorrect Java version, Pterodactyl will automatically prompt you to update like this:

If this does not show up for you, the Java version can be manually changed. Navigate to the "Startup" tab of your server, select Java 21 from the "Docker Image" dropdown as shown in the image below.

note

If you don't see Java 21 in the dropdown, an administrator account is required to update the Paper egg.

The Verifying Installation section does not apply for Pterodactyl.

Verifying Installation

Now that you have installed Java 21, run this command in your terminal to ensure the process was successful.

java -version

The output should be similar to this. The important parts to look out for is that it starts with openjdk 21 and contains 64-Bit in the last line. If the output you get is similar to java: command not found, try creating a new terminal session.

openjdk version "21" 2023-09-19 LTS
OpenJDK Runtime Environment Corretto-21.0.0.35.1 (build 21+35-LTS)
OpenJDK 64-Bit Server VM Corretto-21.0.0.35.1 (build 21+35-LTS, mixed mode, sharing)

If your installation has failed, do not hesitate to reach out in the #paper-help channel of our Discord for support.