Since JDK-8219801 javadoc requires header elements to have consistent order. Various source files in Nashorn do not conform to this.

Reproduce:
cd make/nashorn
ant clean javadoc

Result:
javadoc:
  [javadoc] Generating Javadoc
  [javadoc] Javadoc execution
  [javadoc] /Users/hannes/Work/jdk/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/linker/NameCodec.java:42: error: heading used out of sequence: <H3>, compared to implicit preceding heading: <H1>
  [javadoc] * <h3>Comment from BytecodeName class reproduced here:</h3>
  [javadoc] ^
  [javadoc] /Users/hannes/Work/jdk/src/jdk.dynalink/share/classes/jdk/dynalink/NamespaceOperation.java:92: error: heading used out of sequence: <H3>, compared to implicit preceding heading: <H1>
  [javadoc] * <h3>Operations on multiple namespaces</h3>
  [javadoc] ^
  [javadoc] /Users/hannes/Work/jdk/src/jdk.scripting.nashorn/share/classes/module-info.java:33: error: unexpected heading used: <H1>, compared to implicit preceding heading: <H1>
  [javadoc] * <h1>Usage</h1>
  [javadoc] ^
  [javadoc] /Users/hannes/Work/jdk/src/jdk.scripting.nashorn/share/classes/module-info.java:48: error: unexpected heading used: <H1>, compared to implicit preceding heading: <H1>
  [javadoc] * <h1>Compatibility</h1>
  [javadoc] ^
  [javadoc] /Users/hannes/Work/jdk/src/jdk.scripting.nashorn/share/classes/module-info.java:58: error: unexpected heading used: <H1>, compared to implicit preceding heading: <H1>
  [javadoc] * <h1>Interoperability with the Java platform</h1>
  [javadoc] ^
  [javadoc] 5 errors