Array in Java• Array, element, index(or subscript)• int[] a = new int[12];• int[] a = {31, 28, 31, 30, 31, 30

31, 31, 30, 31, 30, 31};• a[0], a[1],…, and a[11]• a.length• String[] d = {“Sun”, “Mon”, Tue”,

“Wed”, “Thu”, “Fri”, “Sat”};• public static void main(String[] args) {}

Array in Java• Multidimensional array• int[][] b = new int[4][3];• int[][] b = {{1, 2, 3}, {4, 5, 6}

{7, 8, 9}, {0, 1, 2}};• b[0][0], b[0][1],…, b[3][2]• b[0], b[1], b[2], b[3] • b.length(the number of rows), b[0].length,…, b[3].length

Collections in Java

• Generic Collections• ArrayList• LinkedList• List interface

Collection: ArrayList

• ArrayList (java.util package)• ArrayList<String> list1 =

new ArrayList<String>();• Methods: size, get, add(with/without index), remove, clear

Collection: LinkedList

• LinkedList (java.util package)• List<String> list2 = new LinkedList<String>();

• Interface: List (search interface list in java)

• Iterator: ListIterator<String> itr

=list2.listIterator();• itr.hasNext(), itr.next(), itr.hasPrevious(), itr.previous()

Examples