import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.Comparator; import java.util.List; import java.util.ListIterator; public class ArrayLists { public static final Integer[] i = new Integer[] { 10, 20, 30 }; // [0,20,30] public static final Integer[] j = new Integer[] { 60, 70 }; // [60,70] public static final Integer[] k = new Integer[] { 80, 90 }; // [80,90] public static void main(String[] args) { // Create/Initialize List (default) List ls_default = new ArrayList(); // [] // Create/Initialize List with initial capacity 10 List ls_initial_size = new ArrayList(10); // [ , , , , , , , , , ] // Create/Initialize List with existing Collection List ls_collection = new ArrayList<>(Arrays.asList(i)); // [0,20,30] //-----Add Values-------------// ls_collection.add(50); // [0,20,30,50] ls_collection.add(3, 40); // [0,20,30,40,50] ls_collection.addAll(Arrays.asList(k)); // [0,20,30,40,50,80,90] ls_collection.addAll(5, Arrays.asList(j)); // [0,20,30,40,50,60,70,80,90] //-----Size--------// ls_collection.size(); // 9 ls_collection.isEmpty(); // false //-----Find elements----// ls_collection.indexOf(30); // 2 ls_collection.lastIndexOf(50); // 4 ls_collection.contains(90); // true ls_collection.containsAll(Arrays.asList(i)); // true //-----Get and set elements-----// ls_collection.get(4); // 30 ls_collection.set(0, 10); // [10,20,30,40,50,60,70,80,90] ls_collection.subList(0, 3); // [10, 20, 30] //-----Loop over each List item----// System.out.println(ls_collection.toString()); // [10, 20, 30, 40, 50, 60, 70, 80, 90] ls_collection.forEach((val) -> System.out.print(val + " ")); // 10 20 30 40 50 60 70 80 90 System.out.println(); for (Integer val : ls_collection) { System.out.print(val + " "); } // 10 20 30 40 50 60 70 80 90 System.out.println(); ListIterator it = ls_collection.listIterator(); while (it.hasNext()) { System.out.print(it.next() + " "); } // 10 20 30 40 50 60 70 80 90 System.out.println(); //-----Remove elements----// ls_collection.remove(0); // [20,30,40,50,60,70,80,90] ls_collection.remove(ls_collection.size() - 1); // [20,30,40,50,60,70,80] ls_collection.remove(ls_collection.indexOf(20)); // [30,40,50,60,70,80] ls_collection.removeAll(Arrays.asList(j)); // [30,40,50,80] ls_collection.clear(); // [] //----Sort---// ls_default.add(60); ls_default.add(20); ls_default.add(80); ls_default.add(10); Collections.sort(ls_default); // [10, 20, 60, 80] Collections.sort(ls_default, Collections.reverseOrder()); // [80, 60, 20, 10] Collections.sort(ls_default, new Comparator() { @Override public int compare(Integer a, Integer b) { return a.compareTo(b); } }); // [10, 20, 60, 80] } }