Using Queue vs List

It really depends on what kind of list we are talking about.

We want to have a queue so we can have a FIFO structure so when we add a song, it gets added at the back of the queue, while whenever we want to play a song and pop it off, it gets removed from the head of the queue. This is basically what a FIFO data structure is.

The same thing can be accomplished with a list however, depending on the type. For example, we could use an ArrayList and simply add everything as the last element, and when removing, remove the first element. But the Queue interface is more appropriate as we know how add and remove should work for this structure, while in the ArrayList, we would have to add the specified index for each operation to make sure it behaves like a FIFO structure.

In both cases, java will probably do a similar thing (or maybe same even) behind the scenes, it's that the abstraction provided by the Queue interface fits our needs better and we don't have to worry how it works internally as long as add method adds the item at the back of the queue, and the pop method removes an item from the head of the queue.