JDK 17 EA build 26 - javadoc tool now writes message to STDERR instead of STDOUT?

[Jaikiran Pai]

While testing the Apache Ant project with the latest released JDK 17 EA 
(build 26)[1], we have run into an unexpected test failure in our 
project. The test is pretty simple. It launches the javadoc task and 
passes it a Java source file which has javadoc content which is expected 
to raise a warning message. Something like:

package test;

/**
  * This is a test class.
  */
public class Foo {
     /**
      * With a test method.
      * @param baz wrong parameter name should cause warning.
      */
     public void foo(String bar) {}

}

The test then expects the javadoc tool/command to print a message of the 
form "1 warning" to the STDOUT of the launced javadoc process. Of 
course, other log messages are also logged to that STDOUT by the tool.

In JDK version 8, 11 and even 16, this all works as expected and the 
test passes. However, this latest JDK 17 EA, it fails because it doesn't 
find this message on the STDOUT of the process. I looked into this in a 
bit more detail and it looks like the javadoc command/tool is now 
writing this message to the STDERR of the process. Not just that, it 
also looks like the tool is now writing a lot other messages to STDERR, 
which previously were written to STDOUT.

To give you can example, if you directly run the javadoc command from 
JDK 16 and JDK 17 EA build against the above trivial code, you will see 
that in JDK 16, the following were logged to STDOUT:

Loading source file Foo.java...
Constructing Javadoc information...
Building index for all the packages and classes...
Standard Doclet version 16+36-2231
Building tree for all the packages and classes...
Generating ./test/Foo.html...
Generating ./test/package-summary.html...
Generating ./test/package-tree.html...
Generating ./overview-tree.html...
Building index for all classes...
Generating ./allclasses-index.html...
Generating ./allpackages-index.html...
Generating ./index-all.html...
Generating ./index.html...
Generating ./help-doc.html...
1 error
1 warning

and JDK 16 STDERR only had:

Foo.java:9: error: @param name not found
      * @param baz wrong parameter name should cause warning.
               ^
Foo.java:11: warning: no @param for bar
     public void foo(String bar) {}


Now in JDK 17 EA, the same command generates the following STDOUT:

Loading source file Foo.java...
Constructing Javadoc information...

and this STDERR:

Building index for all the packages and classes...
Standard Doclet version 17-ea+26-2439
Building tree for all the packages and classes...
Generating ./test/Foo.html...
Foo.java:9: error: @param name not found
      * @param baz wrong parameter name should cause warning.
               ^
Foo.java:11: warning: no @param for bar
     public void foo(String bar) {}
                 ^
Generating ./test/package-summary.html...
Generating ./test/package-tree.html...
Generating ./overview-tree.html...
Building index for all classes...
Generating ./allclasses-index.html...
Generating ./allpackages-index.html...
Generating ./index-all.html...
Generating ./index.html...
Generating ./help-doc.html...
1 error
1 warning

Given the kind of content now being generated in STDERR, it looks more 
like a bug than an intentional change, but I wanted to check here first 
before filing a JBS issue. Is this an intentional change?

[1] https://jdk.java.net/17/

-Jaikiran