Following degea9’s advice, I changed all HashMap appearances to ConcurrentHashMap in Cocos2dxSound.java:
private final ConcurrentHashMap<String, ArrayList<Integer>> mPathStreamIDsMap = new ConcurrentHashMap<String, ArrayList<Integer>>();
private final ConcurrentHashMap<String, Integer> mPathSoundIDMap = new ConcurrentHashMap<String, Integer>();
also an import is needed:
import java.util.concurrent.ConcurrentHashMap;
And this fixed all of my issues regarding ConcurrentModificationException.
ConcurrentHashMap is thread-safe, which explains everything.
Cheers