Summary

Revert the changes made under JDK-8317544 and temporarily restore the policy of implicit annotation processing by default, until JDK-8321319.

Problem

Build tools have not as of yet adapted to the change in javac's policy.

Solution

With this change, javac will again print the following note:

Annotation processing is enabled because one or more processors were found
on the class path. A future release of javac may disable annotation processing
unless at least one processor is specified by name (-processor), or a search
path is specified (--processor-path, --processor-module-path), or annotation
processing is enabled explicitly (-proc:only, -proc:full).
Use -Xlint:-options to suppress this message.
Use -proc:none to disable annotation processing.

and the "future release" is delayed.

Specification

No specification changes.