In its infinite wisdom, Oracle added a new command line flag in the standard doclet in JDK 8 update release 1.8.0_u121. By default, they now reject any script tags in headers and footers. An example use for these would be to add Google Analytics to the footer of each page of Javadoc. For example see here
The rejection of scripts can be turned off using "--allow-script-in-comments" (note the double hyphen). The new flag can only be added to javadoc in 1.8.0u121 or later. If the flag is added to "additionalparam" and used on earlier releases of JDK 8, it will complain that it is an unrecognised flag.
Sadly, this does not work:
As such, this needs to be exposed as a flag in Maven to provide a way to create a Maven pom.xml that is valid for all JDK 8 releases.
Thread complaining about the lack of release notes: http://mail.openjdk.java.net/pipermail/javadoc-dev/2017-January/thread.html
Issue in Gradle: https://github.com/gradle/gradle/issues/1393