1. No version manager, download and install manually. Not that hard, since it's just a zip file and maybe set JAVA_HOME envvar. If you need multiple versions to co-exist, skip this.
2. Use OS' "native" package manager. Brew, apt, chocolatey.
3. Generic package manager like asdf.
4. SDKMAN!, JBang, jEnv, jabba...
Deciding is easy. But remembering which one you used 6 months ago when you want to install another version...