As pointed out in JDK-8283010, when a bad threadID is passed to the clhsdb "thread" command, the error message is incorrect:

hsdb> thread 18
Couldn't find thread thread

It should say "thread 18", not "thread thread". The code looks like:

                        out.println("Couldn't find thread " + name);

"name" is the name of the command. It should instead use "id".