Java Std Lib Cheatsheet

Commonly used Data Structures¶

Data Objects¶

member	Integer	Double
constants	MAX_VALUE, MIN_VALUE	MAX_VALUE, MIN_VALUE, NaN, POSITIVE_INFINITY, NEGATIVE_INFINITY
methods	parseInt, valueOf	parseDouble, valueOf, intValue, isNaN, isInfinite

String¶

charAt, contains, startsWith, endsWith, format, indexOf, join, split, substring, toCharArray, toLowerCase, toUpperCase, valueOf

Collection Subinterfaces¶

member	List	Set	Map	Queue	Stack	Deque (has Queue, Stack behaviors)
insert	add	add	put, computeIfAbsent	add, offer	push	addFirst, addLast, offerFirst, offerLast
lookup	contains, get, indexOf	contains	containsKey, get, getOrDefault, entrySet	peek	peek, search	getFirst, getLast, peekFirst, peekLast
update	set	-	put, replace	-	-
delete	remove, clear	remove, clear	remove, clear	poll	pop	pollFirst, pollLast, removeFirst, removeLast

Collections methods¶

addAll, clear, contains, containsAll, equals, hashCode, isEmpty, iterator, parallelStream, remove, removeAll, removeIf, retainAll, size, spliterator, stream, toArray, toArray

Iterable methods¶

forEach

Comparable methods¶

compareTo

List¶

member	ArrayList	LinkedList (has Deque behavior)	ArrayBlockingQueue	ArrayDeque
constructor	default, copy, capacity	default, copy	capacity	default, copy, capacity
additional methods	clone, ensureCapacity, sort	-	take, drainTo	-

Hash¶

member	HashSet	HashMap	HashTable
constructor	default, copy, capacity	default, copy, capacity	default, copy, capacity
additional methods	-	clone	clone, rehash

Tree¶

member	PriorityQueue (has Deque behavior)	TreeSet (has Set behavior)
constructor	default, copy, capacity, comparator	default, copy, comparator
additional methods	-	ceiling, floor, first, last, pollFirst, pollLast, higher, lower

Utility¶

StringBuilder¶

append, delete, deleteCharAt, reverse, setLength