Algorithms

All algorithms are referred to by using Collections.algorithm(); for example,

List<Integer> nums = new ArrayList<Integer>();
// nums gets loaded with values
Collections.sort(nums);

void sort(List) sorts a list using merge sort
int frequency(Collection, Object) counts the number of occurrences of Object in Collection
void fill(List, Object) replaces every element of List with Object
boolean disjoint(Collection, Collection) returns true if the two Collections do not share any elements
void shuffle(List) randomly permutes its elements
Other useful algorithms are min(), max(), swap(), copy(), reverse(), binarySearch(), and rotate()