Which Java version you need depends on your application. These guides cover every common release on Debian and Ubuntu, with the exact command for your system.
The number in the error tells you everything: 52 is Java 8, 55 is Java 11, 61 is Java 17, 65 is Java 21. Here is how to find out which Java is really running and how to activate the right version.
Which Java version your application really needs, which one your distribution actually offers, and how to run several versions in parallel and switch between them cleanly.
Java 21 is the current LTS release. Install it on Debian 13 straight from apt, on Debian 12 through the Adoptium repository, or as an Oracle package.
Debian 12 ships OpenJDK 17, Debian 13 no longer does. Here is how to install Java 17 on both, either with apt or through the Adoptium repository with Eclipse Temurin.
On Ubuntu 24.04 LTS and 22.04 LTS, OpenJDK 17 sits right in the official package sources. Here is how to install Java 17 without a PPA and set JAVA_HOME correctly.
Debian ships neither Java 8 nor, from Debian 12 onwards, Java 11. Here is how to install both versions cleanly with apt anyway, using the Adoptium repository and Eclipse Temurin.
Java 8 and Java 11 are still part of the official package sources on Ubuntu 24.04 LTS and 22.04 LTS. Here is how to install the version you need and set it as the default.
