Minor Map tweaks in `NoteBlockAPI`

[JarvisCraft]

NoteBlockAPI/src/main/java/com/xxmicloxx/NoteBlockAPI/NoteBlockAPI.java

Line 32 in 92b6a73

Collections.synchronizedMap(new HashMap<UUID, ArrayList<SongPlayer>>());

Might be replaced with ConcurrentHashMap

NoteBlockAPI/src/main/java/com/xxmicloxx/NoteBlockAPI/NoteBlockAPI.java

Line 54 in 92b6a73

if (plugin.playingSongs.get(player.getUniqueId()) == null) {

Might be replaced with Map#contains or result of Map#get may be cached not to be called twice

[koca2000]

Hi!
Thank you for your suggestions.

As I don't assume that there will not be accessed by many concurrent threads, I do not think that change to ConcurrentHashMap would be useful.

Map#contains has the exact same code as Map#get. I agree that it's result can be cached.

[JarvisCraft]

The reason I suggest usage of ConcurrentHashMap is that at current you use Collections.synchronizedMap which, even in 1-threaded environment is slower due to synchronization of each of its operations.

[JarvisCraft]

<3