Java 21 requirement is never mentioned in the quickstart path

[nthmost-orkes]

Problem

conductor server start requires Java 21+, but neither the README nor the quickstart docs mention this.

The quickstart docs (docs.conductor-oss.org/quickstart) explicitly say:

"You need Node.js (v16+) installed. That's it."

This is wrong — Java 21 is also required, and is the more surprising dependency (most developers have Node already; Java 21 is not a default).

What a new user experiences

1. npm install -g @conductor-oss/conductor-cli — works
2. conductor server start — immediate error:

Error: Java 17 is installed, but Java 21 or higher is required.

Please upgrade your Java installation:
  - macOS: brew install openjdk@21
  ...

Java 17 is the current Homebrew default (brew install openjdk gives you 17, not 21). So most macOS devs will hit this wall immediately.

Secondary issue: if Java 21 is already installed but not in PATH (common — Homebrew installs it but doesn't link it by default), the suggested fix brew install openjdk@21 does nothing visible. The user needs PATH/JAVA_HOME guidance, not just an install command.

Fix

1. Add Java 21+ to prerequisites in README "Get Running in 60 Seconds" section
2. Fix quickstart docs to say "You need Node.js (v16+) and Java 21+ installed."
3. Consider adding a note about PATH/JAVA_HOME for users who have Java 21 installed but not active

Affects

• conductor-oss/conductor README
• conductor-oss/conductor docs/quickstart/index.md
• conductor-oss/conductor-cli (could improve the error message to include PATH/JAVA_HOME guidance)