question: private static ArrayList < GridCollisionJobContextWrapper > slice ( Collection < CollisionJobContext > src , int num ) { ArrayList < GridCollisionJobContextWrapper > slice = new ArrayList < > ( ) ; Iterator < CollisionJobContext > iter = src . iterator ( ) ; for ( int i = 0 ; i < num && iter . hasNext ( ) ; i ++ ) slice . add ( new GridCollisionJobContextWrapper ( iter . next ( ) , i ) ) ; return slice ; }
target:  Takes first n element from contexts list, wrap them and put it into a new list.