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Start your free trialJiawei Hu
9,740 PointsQuestion regarding byArtist method.
In the case of artistSongs == null
, we do:
artistSongs = new ArrayList<>();
(now artistSongs
is just an empty ArrayList
that has No songs in it), and then we put both the artist and this empty ArrayList
of this element into the byArtist()
map and then we go for the next element of the mSongs
SongBook
.
The matter is that we never really manage to put this song into the Map
or the artistSongs ArrayList
and all we did it just create a map element with key equals the author of this song and an empty ArrayList
as value.
Isn't it NOT what we want? Isn't there a line of code missing where it actually adds the song to the newly created artistSongs ArrayList
?
1 Answer
andren
28,558 PointsYou seem to have missed a line of code that was added. At 6:12 Craig adds the following line right below the if
statement:
artistSongs.add(song);
Which adds the song to the list. This line gets executed both when the if
statement is hit and when it is not. So the song is always added to the list.
Jiawei Hu
9,740 PointsJiawei Hu
9,740 PointsThank you!