public void getAllAchievementID(Callback<List<Integer>> callback) throws NullPointerException {
		gw2API.getAllAchievementIDs().enqueue(callback);
	}
public void getAllAchievementID ( Callback < List < Integer > > callback ) throws NullPointerException { gw2API . getAllAchievementIDs ( ) . enqueue ( callback ) ; }
For more info on achievement API go <a href="https://wiki.guildwars2.com/wiki/API:2/achievements">here</a><br/>
Give user the access to {@link Callback#onResponse(Call, Response)} and {@link Callback#onFailure(Call, Throwable)} methods for custom interactions

@param callback callback that is going to be used for {@link Call#enqueue(Callback)}
@throws NullPointerException if given {@link Callback} is empty
@see Achievement achievement info