A DESCRIPTION OF THE PROBLEM :
Nashorn JavaScript engine is deprecated since Java 11 (and scheduled for removal), http://openjdk.java.net/jeps/335. 

If Nashorn ScriptEngine is used in any Java application the following warning is logged (since https://bugs.openjdk.java.net/browse/JDK-8205594 / https://bugs.openjdk.java.net/browse/JDK-8204492) :
"Warning: Nashorn engine is planned to be removed from a future JDK release "

The JDK 11 release notes http://jdk.java.net/11/release-notes indicate the following : 
  "To disable this runtime warning message, users can include the new Nashorn option, --no-deprecation-warning."

Problem : 
1. As far as I am concerned, this indication is very vague and requires knowledge of how nashorn options should be specified. Which is described in another technical notes : https://wiki.openjdk.java.net/display/Nashorn/Nashorn+jsr223+engine+notes
2. I would expect a migration guide to clearly indicate what actions can be implemented by operators to remove a warning, without having to dig deep other documentation (exactly like it was provided in the JDK 9 migration guide for other warning https://docs.oracle.com/javase/9/migrate/toc.htm )

Requested improvement : 
Add a clear section in the Java 11 migration guide regarding this subject, without having to look for other documentation.
For example : 
"
The Nashorn JavaScript Engine [...] have been deprecated [...]. 
The Nashorn engine [...] will print a warning message about deprecation. To disable this runtime warning message, users can include the new Nashorn option, --no-deprecation-warning. [...] [...]
***  This Nashorn option can be specified as a JVM property using -Dnashorn.args="--no-deprecation-warning" ****
"


See discussion with A. Sundararajan on this issue :  https://twitter.com/sundararajan_a/status/1030443026810716160