If you set a breakpoint in a running program and hit that breakpoint right away, that output is somewhat confusing:

class Hello {
    public static void main(String[] args) {
        while (true) {
            int x = 1;
        }
    }
}

$ jdb Hello
Initializing jdb ...
> stop at Hello:4
Deferring breakpoint Hello:4.
It will be set after the class is loaded.
> run
run Hello
Set uncaught java.lang.Throwable
Set deferred uncaught java.lang.Throwable
>
VM Started: Set deferred breakpoint Hello:4

Breakpoint hit: "thread=main", Hello.main(), line=4 bci=0
4 int x = 1;

main[1] clear Hello:4
Removed: breakpoint Hello:4
main[1] cont
> stop at Hello:4

Breakpoint hit: "thread=main", Hello.main(), line=4 bci=0
Set breakpoint Hello:4
4 int x = 1;

main[1] main[1]

You can see what appears to be an extra main[1] prompt. I noticed that the it does not always appear on the last line of output. Sometimes it comes sooner. Then I realized, as you can see above, that the "Set breakpoint" output that is the result of the "stop at" command is being printed after the "Breakpoint hit:" message. If jdb printed the "Set breakpoint" output and prompt before actually setting the breakpoint, you would properly see:

> stop at Hello:4
Set breakpoint Hello:4
> Breakpoint hit: "thread=main", Hello.main(), line=4 bci=0
4 int x = 1;

main[1]

In this case the first main[1] prompt is instead a simple > prompt, and happens before the "Breakpoint hit:" message. If possible, we should make it so all the output of the "stop at" command is produced before actually setting the breakpoint.