How to convert array to collection and vice versa ?

Array to List

Integer[] numArr = {100, 200, 300, 400, 500};

List numList = Arrays.asList(numArr);

Set to Array

Set langSet = new HashSet();

langSet.add("C");

langSet.add("C++");

langSet.add("Java");

langSet.add("Perl");

langSet.add("Sql");

Object[] langArr = langSet.toArray();