A DESCRIPTION OF THE PROBLEM :
The documentation for Doclet.Option#getParameters indicates that it does not return null (but may return an empty string):
https://docs.oracle.com/en/java/javase/11/docs/api/jdk.javadoc/jdk/javadoc/doclet/Doclet.Option.html#getParameters()
https://docs.oracle.com/en/java/javase/13/docs/api/jdk.javadoc/jdk/javadoc/doclet/Doclet.Option.html#getParameters()

However, the examples at
https://openjdk.java.net/groups/compiler/using-new-doclet.html
(in figures 3 and 5) do return null.

Please update either the Javadoc or the example code.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
View the URLs.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Documentation is consistent with examples.
ACTUAL -
Documentation is inconsistent with examples.

FREQUENCY : always