To check whether a HashSet is empty or not, use the isEmpty() method.Create a HashSet −HashSet hs = new HashSet();Add elements to the HashSet −hs.add("B"); hs.add("A"); hs.add("D"); hs.add("E"); hs.add("C"); hs.add("F"); hs.add("K"); hs.add("M"); hs.add("N");Now, check whether the HashSet is empty or not. Since we added elements above, it won’t be empty −hs.isEmpty();The following is an example that checks whether a HashSet is empty or not −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { // create a hash set HashSet hs = ... Read More

Use the size() method to get the size of HashMap. Let us first create a HashMapHashMap hm = new HashMap();Now, add some elements −hm.put("Bag", new Integer(1100)); hm.put("Sunglasses", new Integer(2000)); hm.put("Franes", new Integer(800)); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600));Since, we added 5 elements above, therefore, the size() method will give 5 as the result −set.size()The following is an example to find the size of HashMap −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { // Create a hash map HashMap hm = ... Read More

Elements can be filled in a Java float array in a specified range using the java.util.Arrays.fill() method. This method assigns the required float value in the specified range to the float array in Java.The parameters required for the Arrays.fill() method are the array name, the index of the first element to be filled(inclusive), the index of the last element to be filled(exclusive) and the value that is to be stored in the array elements.A program that demonstrates this is given as follows −Example Live Demoimport java.util.Arrays; public class Demo { public static void main(String[] argv) throws Exception { ... Read More

Elements can be filled in a Java byte array in a specified range using the java.util.Arrays.fill() method. This method assigns the required byte value in the specified range to the byte array in Java.The parameters required for the Arrays.fill() method are the array name, the index of the first element to be filled(inclusive), the index of the last element to be filled(exclusive) and the value that is to be stored in the array elements.A program that demonstrates this is given as follows −Example Live Demoimport java.util.Arrays; public class Demo { public static void main(String[] argv) throws Exception { ... Read More

Use the isEmpty() method to check of a HashMap is empty or not. Let us first create the HashMap −HashMap hm = new HashMap();Now, add some elements −hm.put("Bag", new Integer(1100)); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600));Since, we added elements above, therefore, the HashMap isn’t empty. Let us check −set.isEmpty()The following is an example to check if a HashMap is empty or not −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { // Create a hash map HashMap hm = new HashMap(); ... Read More

To create a HashMap, use the HashMap class −HashMap hm = new HashMap();Add elements to the HashMap in the form of key-value pair −hm.put("Bag", new Integer(1100)); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600));The following is an example to create HashMap and add key-value pair −Example Live Demoimport java.util.*; public class Demo {    public static void main(String args[]) {       // Create a hash map       HashMap hm = new HashMap();       // Put elements to the map       hm.put("Bag", new Integer(1100));       hm.put("Wallet", new Integer(700));       hm.put("Belt", new Integer(600)); ... Read More

Create a HashMap −HashMap hm = new HashMap();Add elements to the HashMap that we will be displaying afterward −hm.put("Maths", new Integer(98)); hm.put("Science", new Integer(90)); hm.put("English", new Integer(97)); hm.put("Physics", new Integer(91));Now, to display the HashMap elements, use Iterator. The following is an example to display HashMap elements −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { // Create a hash map HashMap hm = new HashMap(); // Put elements to the map ... Read More

Use the size() method to get the count of elements.Let us first create a HashMap and add elements −HashMap hm = new HashMap(); // Put elements to the map hm.put("Maths", new Integer(98)); hm.put("Science", new Integer(90)); hm.put("English", new Integer(97));Now, get the size −hm.size()The following is an example to get the count of HashMap elements −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { // Create a hash map HashMap hm = new HashMap(); // Put elements ... Read More

To add elements to HashMap, use the put() method.First, create a HashMap −HashMap hm = new HashMap();Now, let us add some elements to the HashMap −hm.put("Maths", new Integer(98)); hm.put("Science", new Integer(90)); hm.put("English", new Integer(97));The following is an example to add elements to HashMap −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { // Create a hash map HashMap hm = new HashMap(); // Put elements to the map hm.put("Maths", ... Read More

To retrieve the set of keys from HashMap, use the keyset() method. However, for set of values, use the values() method.Create a HashMap −HashMap hm = new HashMap(); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600)); hm.put("Backpack", new Integer(1200));Now, retrieve the keys −Set keys = hm.keySet(); Iterator i = keys.iterator(); while (i.hasNext()) { System.out.println(i.next()); }Retrieve the values −Collection getValues = hm.values(); i = getValues.iterator(); while (i.hasNext()) { System.out.println(i.next()); }The following is an example to get the set of all keys and values in HashMap −Example Live Demoimport java.util.*; public class Demo { public static ... Read More