CHEAT SHEET
Constructing Various Collections
List<Integer> list = new ArrayList<Integer>();
Queue<Double> queue = new LinkedList<Double>();
Stack<String> stack = new Stack<String>();
Set<String> words = new HashSet<String>();
Map<String, Integer> counts = new TreeMap<String, Integer>();
Methods Found in ALL collections (Lists, Stacks, Queues, Sets, Maps)
clear()
removes all elements of the collection
equals(collection)
returns true if the given other collection contains the same elements
isEmpty()
returns true if the collection has no elements
size()
returns the number of elements in the collection
toArray()
returns an array of the elements in this collection
toString()
returns a string representation such as "[10, -2, 43]"
Methods Found in both Lists and Sets (ArrayList, LinkedList, HashSet, TreeSet)
add(value)
adds value to collection (appends at end of list)
contains(value)
returns true if the given value is found somewhere in this collection
iterator()
returns an Iterator object to traverse the collection's elements
remove(value)
finds and removes the given value from this collection
removeAll(collection)
removes any elements found in the given collection from this one
retainAll(collection)
removes any elements not found in the given collection from this one
List<E> Methods (10.1)
add(index, value)
inserts given value at given index, shifting subsequent values right
indexOf(value)
returns first index where given value is found in list (-1 if not found)
get(index)
returns the value at given index
lastIndexOf(value)
returns last index where given value is found in list (-1 if not found)
remove(index)
removes/returns value at given index, shifting subsequent values left
set(index, value)
replaces value at given index with given value
subList(from, to)
returns sub-portion at indexes from (inclusive) and to (exclusive)
Stack<E> Methods
peek()
returns the top value from the stack without removing it
pop()
removes the top value from the stack and returns it;
peek/pop throw an EmptyStackException if the stack is empty
push(value)
places the given value on top of the stack
Queue<E> Methods
add(value)
places the given value at the back of the queue
peek()
returns the front value from the queue without removing it;
returns null if the queue is empty
remove()
removes the value from the front of the queue and returns it;
throws a NoSuchElementException if the queue is empty
