Is there a scenario where you would be writing a bot for this online game and need access to the javadocs while offline?
Having no access to the bot source - You could recursively `wget --mirror --convert-links --adjust-extension --page-requisites --no-parent` the entirety of the javadocs but given they're generated automatically with updates your supposed offline copy would fall out of date in just a few days.
The javadocs are also well indexed on search engines such as Google, too. Making it easy for dreambot search terms to lead to a relevant and helpful javadocs page.