Streams learning point

You can turn a Java String into an IntStream, but that's annoyingly different to a regular Stream.

Getting a map of character counts:

s.chars()
    .collect(
        HashMap<Integer,Integer>::new,
        (map, value)->{
            Integer oldCount = map.get(value);
            map.put(value, null == oldCount ? 1 : oldCount + 1 );
        },
        HashMap::putAll
    )

Hmm, that's a lot of map-making boilerplate inside the collect bit. We can make it a Stream<Integer> and it's much simpler:

s.chars()
    .boxed()  // this bit makes collect easier
    .collect(
        Collectors.toMap(
            i->i,
            i->1,
            (i,b)->i+1
        )
    )

It's funny how the first example is now considered "boilerplate". Imagine doing it with anonymous inner classes instead of lambdas and method references.

It's also funny how chaining methods is the new normal. Some places where I worked would have to change their style guide.

Even *more* Maven/Eclipse test nonsense

We have learned how to run one test from Maven, and how to tell Maven you want to debug the test.

But if you want to use jdb as your debugger, you need to connect it something like this:

jdb -connect com.sun.jdi.SocketAttach:hostname=localhost,port=5005 -sourcepath src\test\java\;src\main\java\