A DESCRIPTION OF THE PROBLEM :
running with jdwp or jfr flags turned on would show their respective startup messages
these message should be printed to stderr instead of stdout as stdout should be used for data output and stderr used for auxiliary messages

currently they're hard-coded to print to stdout, there should be a flag to redirect them to stderr. we should even consider to change the default behavior to print to stderr

relevant code: https://github.com/AdoptOpenJDK/openjdk-jdk11/blob/19fb8f93c59dfd791f62d41f332db9e306bc1422/src/jdk.jdwp.agent/share/native/libjdwp/error_messages.c#L119

sample java command line: java -XX:StartFlightRecording -agentlib:jdwp=transport=dt_socket,server=y,suspend=n

sample stdout output(should be none):
Listening for transport dt_socket at address: 23110
Started recording 1. No limit specified, using maxsize=250MB as default.

Use jcmd 2649129 JFR.dump name=1 filename=FILEPATH to copy recording data to file.