See Release Notes of jdk8u121:
> tools/javadoc(tool)
> New --allow-script-in-comments option for javadoc
> The javadoc tool will now reject any occurrences of JavaScript code in
> the javadoc documentation comments and command-line options, unless the
> command-line option, --allow-script-in-comments is specified.
>
> With the --allow-script-in-comments option, the javadoc tool will
> preserve JavaScript code in documentation comments and command-line
> options. An error will be given by the javadoc tool if JavaScript
> code is found and the command-line option is not set.
> JDK-8138725 (not public)
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