Platform links, introduced in JDK-8216497, rely on package/element lists for each version of Java supported by javadoc. Element lists for JDK >= 11 are created dynamically at build time. However, these lists are only available in the javadoc version built as part of the JDK image, not the interim version of javadoc used to create the documentation.

This went unnoticed because the interim version of javadoc does not use the platform link feature when producing documentation for the platform libraries themselves. However, using it to document select platform modules that do not include java.base triggers the following warning:

javadoc: warning - Error reading resource: resources/releases/element-list-16.txt

List of package/element lists in JDK build dir:

build/macosx-x64/buildtools/interim_langtools_modules/jdk.javadoc.interim/jdk/javadoc/internal/doclets/toolkit/resources/releases/element-list-10.txt
build/macosx-x64/buildtools/interim_langtools_modules/jdk.javadoc.interim/jdk/javadoc/internal/doclets/toolkit/resources/releases/package-list-8.txt
build/macosx-x64/buildtools/interim_langtools_modules/jdk.javadoc.interim/jdk/javadoc/internal/doclets/toolkit/resources/releases/package-list-9.txt
build/macosx-x64/buildtools/interim_langtools_modules/jdk.javadoc.interim/jdk/javadoc/internal/doclets/toolkit/resources/releases/package-list-7.txt
build/macosx-x64/jdk/modules/jdk.javadoc/jdk/javadoc/internal/doclets/toolkit/resources/releases/element-list-14.txt
build/macosx-x64/jdk/modules/jdk.javadoc/jdk/javadoc/internal/doclets/toolkit/resources/releases/element-list-15.txt
build/macosx-x64/jdk/modules/jdk.javadoc/jdk/javadoc/internal/doclets/toolkit/resources/releases/element-list-16.txt
build/macosx-x64/jdk/modules/jdk.javadoc/jdk/javadoc/internal/doclets/toolkit/resources/releases/element-list-12.txt
build/macosx-x64/jdk/modules/jdk.javadoc/jdk/javadoc/internal/doclets/toolkit/resources/releases/element-list-13.txt
build/macosx-x64/jdk/modules/jdk.javadoc/jdk/javadoc/internal/doclets/toolkit/resources/releases/element-list-11.txt
build/macosx-x64/jdk/modules/jdk.javadoc/jdk/javadoc/internal/doclets/toolkit/resources/releases/element-list-10.txt
build/macosx-x64/jdk/modules/jdk.javadoc/jdk/javadoc/internal/doclets/toolkit/resources/releases/package-list-8.txt
build/macosx-x64/jdk/modules/jdk.javadoc/jdk/javadoc/internal/doclets/toolkit/resources/releases/package-list-9.txt
build/macosx-x64/jdk/modules/jdk.javadoc/jdk/javadoc/internal/doclets/toolkit/resources/releases/package-list-7.txt