Collection

Question 1

Sorting Helpers

Answer 1

Collections.sort(List, Comparator)

Array.sort([], Comparator)

Question 2

Comparable

Answer 2

public int compareTo(T other)

0 - both objects are equal
negative - This object is less than given object
positive - This object is greater than given object

Question 3

Comparator

Answer 3

Interface to compare two objects.

public int compare(T ti, T t2)