OpenJDK 16 GA is scheduled for 2021/03/16. So we should implement
support with PMD 6.32.0

The following JEPs are important for us:

• JEP 394: Pattern Matching for instanceof
  • Was in JDK14+JDK15 a preview feature
  • In JDK16 it will be a standard feature
• JEP 395: Records
  • Was in JDK14+JDK15 a preview feature
  • In JDK16 it will be a standard feature
• JEP 397: Sealed Classes (Second Preview)

In summary: https://javaalmanac.io/jdk/16/

This issue is similar to the previous: #2646

EA Release of JDK16 is available here: http://jdk.java.net/16/

Tasks: see #3111