Programming Articles - Page 2904 of 3363

LinkedHashMap is a data structure in Java that is part of the Java Collections Framework. It is very similar to HashMap.It stores key-value pairs, where each key is unique, and it allows null values, but allows only one null key. The main difference is that the LinkedHashMap returns the elements in the order they were inserted. This is because it maintains a linked list with entries in the map, which helps it to retain the insertion order of the elements. Our task is to check if a particular key exists in a LinkedHashMap in Java. Scenario 1 Following is a ... Read More

To clone the IdentityHashMap in Java, use the clone() method.Create an IdentityHashMap and add elements to it −IdentityHashMap m = new IdentityHashMap(); m.put("1", 100); m.put("2", 200); m.put("3", 300); m.put("4", 150); m.put("5", 110);Now get the size of the IdentityHashMap −m.size()The following is an example to clone IdentityHashMap in Java −Example Live Demoimport java.util.*; public class Demo {    public static void main(String[] args) {       IdentityHashMap 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); ... Read More

To remove all the elements from LinkedHashSet in Java, use the clear() method.The following is an example to declare LinkedHashSet and add elements to it −LinkedHashSet hashSet = new LinkedHashSet(); hashSet.add(10); hashSet.add(20); hashSet.add(30); hashSet.add(40); hashSet.add(50); hashSet.add(60);Use the clear() method to remove all elements −hashSet.clear();The following is an example −Example Live Demoimport java.util.LinkedHashSet; public class Demo { public static void main(String[] args) { LinkedHashSet hashSet = new LinkedHashSet(); hashSet.add(10); hashSet.add(20); hashSet.add(30); ... Read More

To create NavigableMap from TreeMap. The following is the declaration −NavigableMap n = new TreeMap();Now, add some elements to the NavigableMap created above −n.put("A", 888); n.put("B", 999); n.put("C", 444); n.put("D", 555); n.put("E", 666); n.put("F", 888); n.put("G", 999); n.put("H", 444); n.put("I", 555); n.put("J", 666);The following is an example to create NavigableMap from TreeMap and display it −Example Live Demoimport java.util.*; public class Demo { public static void main(String[] args) { NavigableMap n = new TreeMap(); n.put("A", 888); n.put("B", 999); ... Read More

To remove a specified element from LinkedHashSet, use the remove() and include the element you want to remove as a parameter.First, set LinkedHashSet and add elements −LinkedHashSet hashSet = new LinkedHashSet(); hashSet.add(10); hashSet.add(20); hashSet.add(30); hashSet.add(40); hashSet.add(50); hashSet.add(60);Let us now remove an element −hashSet.remove(10);The following is an example to remove specified element from LinkedHashSet −Example Live Demoimport java.util.LinkedHashSet; public class Demo { public static void main(String[] args) { LinkedHashSet hashSet = new LinkedHashSet(); hashSet.add(10); hashSet.add(20); ... Read More

Use the NavigableMap ceilingEntry() method to returna key-value mapping associated with the least key greater than or equal to the given keyThe following is an example to implement ceilingEntry() method −Example Live Demoimport java.util.*; public class Demo { public static void main(String[] args) { NavigableMap n = new TreeMap(); n.put(5, "Tom"); n.put(9, "John"); n.put(14, "Jamie"); n.put(1, "Tim"); n.put(4, "Jackie"); n.put(15, "Kurt"); n.put(19, "Tiger"); n.put(24, "Jacob"); System.out.println("NavigableMap elements..."+n); System.out.println("Ceiling Entry = " + n.ceilingEntry(11)); } }OutputNavigableMap elements... {1=Tim, 4=Jackie, 5=Tom, 9=John, 14=Jamie, 15=Kurt, 19=Tiger, 24=Jacob} Ceiling Entry = 14=Jamie

The higher() method in NavigableSet returns the least element strictly greater than the given element i.e. 35 here −higher(35);The following is an example to implement the higher method in Java −Example Live Demoimport java.util.NavigableSet; import java.util.TreeSet; public class Demo { public static void main(String[] args) { NavigableSet set = new TreeSet(); set.add(10); set.add(25); set.add(40); set.add(55); set.add(70); set.add(85); set.add(100); System.out.println("Returned Value = " + set.higher(35)); } }OutputReturned Value = 40

The floor() method returns the greatest element less than or equal to the given element i.e. 30 here −floor(30)The following is an example to implement the floor method in Java −Example Live Demoimport java.util.NavigableSet; import java.util.TreeSet; public class Demo { public static void main(String[] args) { NavigableSet set = new TreeSet(); set.add(10); set.add(25); set.add(40); set.add(55); set.add(70); set.add(85); set.add(100); System.out.println("Returned Value = " + set.floor(30)); } }OutputReturned Value = 25

With Java, you can initialize a set without using add() method.For this create a string array −String arr[] = { "A", "B", "C", "D", "E"};Now, use Set and asList() method to initialize the above string array to our Set −Set s = new HashSet(Arrays.asList(arr));The following is an example to initialize a set without using add() method −Example Live Demoimport java.util.Arrays; import java.util.HashSet; import java.util.Set; public class Demo { public static void main(String[] a) { String arr[] = { "A", "B", "C", "D", "E"}; Set s = ... Read More

The NavigableMap put() method is used to set a specific key and value in the NavigableMap.The following is an example to implement NavigableMap put() method −Example Live Demoimport java.util.*; public class Demo { public static void main(String[] args) { NavigableMap n = new TreeMap(); n.put(5, "Tom"); n.put(9, "John"); n.put(14, "Jamie"); n.put(1, "Tim"); n.put(4, "Jackie"); n.put(15, "Kurt"); ... Read More