Tool
Which Java version do I need?
Pick the Minecraft version you run, or the one you want to move to. The requirement comes straight from Mojang's own version metadata, which is the same value the game checks when it starts.
Runtimes that will start it
Every Java version we track at or above the requirement.
- Java 21required minimumLTSbuilds available
- Java 22newerbuilds available
- Java 23newerbuilds available
- Java 24newerbuilds available
- Java 25newerLTSbuilds available
- Java 26newerbuilds available
Too old, will not start: Java 8, Java 11, Java 16, Java 17, Java 18, Java 19, Java 20
Server software for 1.21.2
Each one targets the same runtime requirement.
What this does and does not tell you
A runtime older than Java 21 will refuse to start this version. The check happens before the world loads, so it fails immediately rather than corrupting anything.
Source: Mojang version metadata
Server software built for this version targets the same runtime. Running a much newer Java than the server software was built against is where problems usually appear, not the game itself.
Source: Server software release notes
1.21.2 was released 22 Oct 2024 and speaks protocol 768. Everything about this version
Frequently asked
How do I know which Java version my Minecraft server needs?
Mojang publishes a required Java version in the metadata for every Minecraft version. This tool reads that value directly, so the answer is the same one the game checks at startup rather than an estimate.
Will a newer Java version work?
Usually, but nobody publishes a guarantee per version. A runtime older than the requirement will refuse to start. A newer one normally runs, and the risk sits with the server software and the plugins rather than with the game itself.
What happens if the Java version is too old?
The server refuses to start and prints an error naming the required version. It fails before loading a world, so nothing is damaged.
Do mods and plugins change the Java requirement?
They can raise it. A plugin compiled for a newer Java than your runtime will fail to load even when the server starts. The version requirement here is the floor for the game, not for everything you install on it.