With docker, the recommended method of using jcmd with containerized JVMs is to run "jcmd" as root (see comments in JDK-8255008).

However, this will not work with podman (at least on some versions of Linux).
With podman, you should run both the container and jcmd using the same host UID.

=========
Suggested fix:
[1] Make jcmd work even if launched by root; or
[2] If jcmd is launched by root, do not try to connect to any PIDs that the root user cannot access, to avoid the mysterious "java.io.IOException" errors.

=========
Ubuntu 20.10
podman version 3.2.1

$ mkdir -p my-java-app
$ cd my-java-app
$ cat > Dockerfile <<EOF
FROM container-registry.oracle.com/java/openjdk:17
COPY Wait.class /
CMD ["java", "-cp", "/", "Wait"]
EOF
$ cat > Wait.java << END
public class Wait {
    public static void main(String args[]) throws Throwable {
        System.out.println("pid = " + ProcessHandle.current().pid() + "; Type Return to exit");
        System.in.read();
    }
}
END
$ javac Wait.java
$ podman build -t my-java-app .
$ podman run -it --tty=true --rm my-java-app java -cp / Wait
pid = 1; Type Return to exit

# ----------- In a different console ---------------
$ ps -ef | grep Wait
ubuntu 20523 17918 3 20:52 pts/0 00:00:00 podman run --rm localhost/my-java-app java -cp / Wait
ubuntu 20551 20537 5 20:52 ? 00:00:00 java -cp / Wait
$ jcmd Wait VM.version
20551:
OpenJDK 64-Bit Server VM version 17.0.1+12-39
JDK 17.0.1
$ sudo jcmd Wait VM.version
20551:
java.io.IOException: Broken pipe
at jdk.attach/sun.tools.attach.VirtualMachineImpl.write(Native Method)
at jdk.attach/sun.tools.attach.VirtualMachineImpl.writeString(VirtualMachineImpl.java:324)
at jdk.attach/sun.tools.attach.VirtualMachineImpl.execute(VirtualMachineImpl.java:175)
at jdk.attach/sun.tools.attach.HotSpotVirtualMachine.executeCommand(HotSpotVirtualMachine.java:310)
at jdk.attach/sun.tools.attach.HotSpotVirtualMachine.executeJCmd(HotSpotVirtualMachine.java:292)
at jdk.jcmd/sun.tools.jcmd.JCmd.executeCommandForPid(JCmd.java:124)
at jdk.jcmd/sun.tools.jcmd.JCmd.main(JCmd.java:97)

$ podman images
REPOSITORY TAG IMAGE ID CREATED SIZE
localhost/my-java-app latest f50ae9c32edf 6 minutes ago 597 MB
container-registry.oracle.com/java/openjdk 17 ba8d3012271a 3 weeks ago 597 MB