Get Random Element from Collection

private Object getRandomObject(Collection from) {
   Random rnd = new Random();
   int i = rnd.nextInt(from.size());
   return from.toArray()[i];
}

Using Lambdas you can do this quite quickly and handle the case when Collection is empty.

public static <E> Optional<E> getRandom (Collection<E> e) {

    return e.stream()
            .skip((int) (e.size() * Math.random()))
            .findFirst();
}

The most efficient it to only iterate as far as you need.

public static <T> T random(Collection<T> coll) {
    int num = (int) (Math.random() * coll.size());
    for(T t: coll) if (--num < 0) return t;
    throw new AssertionError();
}