It, well, sort of, approximately, just about, allows you to pretend that all accessible
static members of the class you import them from are like
private static members of the class you imported them into. It was ontroduced in Java5. Before that (Java1.4−), people would sometimes extend from a class with
public constants (or implement such an interface), meaning those constants become
public members of the new class, which is often not what you want. You will find that called the, “constant interface anti‑
pattern.” If you look up that class, you find it has lots of
public static final fields(←link). Rather than writing
ShortMessage.ACTIVE_SENSING, you can import that field and simply write
ACTIVE_SENSING. The asterisk means you are importing all
static members of that class. I prefer to name the fields being imported.
