Beginning Java forum??? Okay, I respect your feelings so I'll leave it there.
So what I did was, I went into the API and used the "USE" link at the top to find all methods in the standard API which return a LocalTime object. Some of them looked promising but they all ended up with the same error message, no doubt the one you have already seen a thousand times.
And then I was looking through the DateTimeFormatter API to see if I could see a way to sneak in an hour and minute without having to provide anything in the string being passed. Of course there isn't any way, but I saw this in the section about "Resolving":
6. A LocalTime is formed if there is at least an hour-of-day available. This involves providing default values for minute, second and fraction of second.
Which is backwards from what you want, you want to provide default values for hour and minute. So I gave up and produced this sleazy hack which provides an hour-of-day:
It turned out I also had to provide a minute value, otherwise I got the dreaded error message again, but it was already a sleazy hack so, whatever.
Probably when Rob or Stephan show up they will have the non-sleazy-hack version, but at least that's working code.