There seems to be be a lack of clarity by users on the distinction between the Java runtime / JDK required to run the Jenkins system and the JDK available to jobs within Jenkins (examples here, here, and more).
Suggest perhaps a line break, emphasis and a link to JDK installer plugins as a step towards better clarity.
Jenkins jobs may be executed on Java versions different from the controller/agent runtime.
Generally, Jenkins allows ANY version of JRE/JDK to be invoked during the job execution. It includes:
Installation and execution of build steps using JDK managed by JDK tool installers.
Execution of Java commands from CLI
Also suggest a heading change from "Running Jenkins" to Running Jenkins system".
Both installers could do with better guidance on the installation, configuration and usage, which is a separate matter.