Found 9326 Articles for Object Oriented Programming

To get Head Set, you need to use the headset() method. This allow a user to get a set of elements in sorted order.Firstly, set the TreeSet and add elementsTreeSet tSet = new TreeSet(); tSet.add("P"); tSet.add("Q"); tSet.add("R"); tSet.add("S");Let us now get the Head SetSortedSet s = tSet.headSet("S");The following is an example to get Head Set from TreeSet in JavaExample Live Demoimport java.util.*; public class Demo {    public static void main(String args[]){       TreeSet tSet = new TreeSet();       tSet.add("P");       tSet.add("Q");       tSet.add("R");       tSet.add("S");       System.out.println("TreeSet elements..."); ... Read More

Create TreeSet and add elements to itTreeSet tSet = new TreeSet(); tSet.add("P"); tSet.add("Q"); tSet.add("R"); tSet.add("S");Now, let us traverse elements in descending orderIterator j = tSet.descendingIterator(); while(j.hasNext()) {    System.out.println(j.next()); }The following is an example to traverse TreeSet elements in descending orderExample Live Demoimport java.util.*; public class Demo {    public static void main(String args[]){       TreeSet tSet = new TreeSet();       tSet.add("P");       tSet.add("Q");       tSet.add("R");       tSet.add("S");       System.out.println("TreeSet elements...");       Iterator i = tSet.iterator();       while(i.hasNext()){          System.out.println(i.next());     ... Read More

To get the size of IdentityHashMap, use the size() method. It returns the count of elements in the IdentityHashMap.Let us first create a IdentityHashMap and add some elements to itMap m = new IdentityHashMap(); m.put("1", 100); m.put("2", 200); m.put("3", 300); m.put("4", 150); m.put("5", 110); m.put("6", 50); m.put("7", 90); m.put("8", 250); m.put("9", 350); m.put("10", 450);Now, get the sizem.size();The following is an example to get the size of the IdentityHashMapExample Live Demoimport java.util.*; public class Demo { public static void main(String[] args) { Map m = newIdentityHashMap(); m.put("1", ... Read More

To get the set of values in IdentityHashMap, use the values() method.First, set the IdentityHashMapMap m = new IdentityHashMap(); m.put("1", 100); m.put("2", 200); m.put("3", 300); m.put("4", 150); m.put("5", 110); m.put("6", 50); m.put("7", 90); m.put("8", 250); m.put("9", 350); m.put("10", 450);Now, retrieve the set of valuesm.values()The following is an example to get the set of values in IdentityHashMap using values() methodExample Live Demoimport java.util.*; public class Demo { public static void main(String[] args) { Map m = newIdentityHashMap(); m.put("1", 100); m.put("2", 200); ... Read More

To check whether a HashSet contains another, use the contains() method.Set the first HashSetString strArr[] = { "P", "Q", "R" }; Set set1 = new HashSet(Arrays.asList(strArr));Set the second HashSetString strArr = new String[] { "P", "Q"}; Set set2 = new HashSet(Arrays.asList(strArr));Check nowset1.containsAll(set2))The following is an example to check if a HashSet collection in Java contains another CollectionExample Live Demoimport java.util.Arrays; import java.util.HashSet; import java.util.Set; public class Demo { public static void main(String[] a) { String strArr[] = { "P", "Q", "R" }; Set set1 = new ... Read More

To fetch the value for a specific key, use the get() method.As a parameter, set the key you want to fetch and fetch the value.Let’s say you need to fetch value of key 3get("3")The following is an example to fetch the value for a specific key in Java IdentityHashMap −Example Live Demoimport java.util.*; public class Demo {    public static void main(String[] args) {       Map m = newIdentityHashMap();       m.put("1", 100);       m.put("2", 200);       m.put("3", 300);       m.put("4", 150);       m.put("5", 110);       m.put("6", 50); ... Read More

Use the remove() method to remove an element from IdentityHashMap.Let us create IdentityHashMap and add some elementsMap m = new IdentityHashMap(); m.put("1", 100); m.put("2", 200); m.put("3", 300); m.put("4", 150); m.put("5", 110); m.put("6", 50); m.put("7", 90); m.put("8", 250); m.put("9", 350); m.put("10", 450);Let’s say you need to remove 2 from the Map. For that, use the remove() methodm.remove("2");The following is an example to remove an element from Java IdentityHashMapExample Live Demoimport java.util.*; public class Demo {    public static void main(String[] args) {       Map m = new IdentityHashMap(); m.put("1", 100); ... Read More

Check whether a Map is empty or not using the isEmpty() method.Let us first create a IdentityHashMap and add some elements to itMap m= new IdentityHashMap(); m.put("1", 100); m.put("2", 200); m.put("3", 300); m.put("4", 150); m.put("5", 110); m.put("6", 50); m.put("7", 90); m.put("8", 250); m.put("9", 350); m.put("10", 450);Now, use the following method to check whether the Map is empty or not. Since we added some elements above, therefore the Map is not emptyn.isEmpty();Example Live Demoimport java.util.*; public class Demo {    public static void main(String[] args) {       Map m = new IdentityHashMap(); m.put("1", 100); m.put("2", 200); m.put("3", 300); m.put("4", 150); ... Read More

The floorKey() method is used to get floor key i.e. to return the greatest key less than or equal to the given key, or null if there is no such key.The following is an example to get floor key from NavigableMapExample Live Demoimport java.util.*; public class Demo {    public static void main(String[] args) {       NavigableMap n = new TreeMap();       n.put("A", 498);       n.put("B", 389);       n.put("C", 868);       n.put("D", 988);       n.put("E", 686);       n.put("F", 888);       n.put("G", 999);       ... Read More

The first and last elements of a Linked List can be obtained using the methods java.util.LinkedList.getFirst() and java.util.LinkedList.getLast() respectively. Neither of these methods require any parameters.A program that demonstrates this is given as followsExample Live Demoimport java.util.LinkedList; public class Demo { public static void main(String[] args) { LinkedList l = new LinkedList(); l.add("John"); l.add("Sara"); l.add("Susan"); l.add("Betty"); l.add("Nathan"); ... Read More