How to configure and use an early-access JDK in Eclipse?

Issue

I want to try JDK21 Early Access release but I don't see a compliance level of 21 or even 20 which is GA already.

In the latest official Eclipse distro highest level is 17. In the latest Spring IDE the highest level is 18

How do I go about trying new features of JDK21 Early Access release from an IDE?

PS: I am going to need the new language features, so its not simply old java code running on a new VM.

Solution

If it's the same as previous releases, I would expect Java 21 BETA to appear on the Eclipse marketplace in September 2023.

Java 20 Support for Eclipse 2023-03 (4.27)
https://marketplace.eclipse.org/content/java-20-support-eclipse-2023-03-427

Java 21 Support for Eclipse 2023-09 (4.29) Unreleased
https://marketplace.eclipse.org/content/java-21-support-eclipse-2023-09-429

Java 21 implementation progress
https://github.com/eclipse-jdt/eclipse.jdt.core/issues?q=milestone%3ABETA_JAVA21

Answered By - cypher256