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Articles by karthikeya Boyini
Page 10 of 143
Make a Hashtable read-only in Java
Read-only Hashtable would mean users won’t be able to add or remove elements from it. Let us first create a Hashtable with key-value pair −Hashtablehash = new Hashtable(); hash.put("1", "A"); hash.put("2", "B"); hash.put("3", "C"); hash.put("4", "D"); hash.put("5", "E"); hash.put("6", "F"); hash.put("7", "G");Now, use unmodifiableMap() to form a Hashtable read-only −Mapm = Collections.unmodifiableMap(hash);Exampleimport java.util.Collections; import java.util.Hashtable; import java.util.Map; public class Demo { public static void main(String[] s) { Hashtablehash = new Hashtable(); hash.put("1", "A"); hash.put("2", "B"); hash.put("3", "C"); hash.put("4", "D"); hash.put("5", "E"); ...
Read MoreJava Program to get the reverse of the NavigableSet
We will create a NavigableSet collection and add some elements −NavigableSet set = new TreeSet(); set.add("ABC"); set.add("DEF"); set.add("GHI"); set.add("JKL"); set.add("MNO"); set.add("PQR"); set.add("STU");Now, use descendingSet() for the reverse of NavigableSet −NavigableSetreverse = set.descendingSet();Exampleimport java.util.NavigableSet; import java.util.TreeSet; public class Demo { public static void main(String[] args) { NavigableSet set = new TreeSet(); set.add("ABC"); set.add("DEF"); set.add("GHI"); set.add("JKL"); set.add("MNO"); set.add("PQR"); set.add("STU"); NavigableSetreverse = set.descendingSet(); System.out.println("NavigableSet = " + set); System.out.println("NavigableSet ...
Read MoreJava Program to get day of week for the last day of each month in 2019
For last day of each month, at first create a List collection for day of week −ListdayOfWeek = new ArrayList();Now, get day of week for the last day of each month in 2019, set the year using withYear() and use lastDayOfMonth() and getDayOfWeek methods −for (Month m: Month.values()) { DayOfWeek days = LocalDate.now().withYear(2019).with(m).with(TemporalAdjusters.lastDayOfMonth()).getDayOfWeek(); }Exampleimport java.time.DayOfWeek; import java.time.LocalDate; import java.time.Month; import java.time.temporal.TemporalAdjusters; import java.util.ArrayList; import java.util.List; public class Demo { public static void main(String[] argv) { ListdayOfWeek = new ArrayList(); for (Month m: Month.values()) { DayOfWeek days = LocalDate.now().withYear(2019).with(m).with(TemporalAdjusters.lastDayOfMonth()).getDayOfWeek(); ...
Read MoreDoubleBuffer arrayOffset() method in Java
The offset of the first element of the buffer inside the buffer array is obtained using the method arrayOffset() in the class java.nio.DoubleBuffer. If the buffer backed by the array is read-only, then the ReadOnlyBufferException is thrown.A program that demonstrates this is given as follows −Exampleimport java.nio.*; import java.util.*; public class Demo { public static void main(String[] args) { int n = 5; try { DoubleBuffer buffer = DoubleBuffer.allocate(5); buffer.put(4.5D); buffer.put(1.2D); buffer.put(3.9D); buffer.put(7.5D); ...
Read MoreWebsite Blocker Using Python
If you are working in a big IT company then you may notice that their couple of websites are blocked especially social networking sites like facebook, youtube, Instagram etc.Instead of using third-party applications to blocks certain website, we can develop our own custom application which will block websites of our choice and developing a website blocker in python is not so difficult too. That’s what we going to do- develop a python script which will block the website we want.Prerequisite:Python 3.x installedBasic knowledge of PythonWhat we are going to do:We are going to develop python application which will block a ...
Read MoreNavigableMap size() Method in Java
To get the size of NavigableMap, use the size() method. It returns the count of elements in the NavigableMap.Let us first create a NavigableMap and add some elements to it −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");Now, get the size −n.size();The following is an example to implement the size() method to get the size of the NavigableMap −Exampleimport java.util.*; public class Demo { public static void main(String[] args) { NavigableMap n = new TreeMap(); ...
Read MoreUse ListIterator to traverse an ArrayList in the forward direction in Java
A ListIterator can be used to traverse the elements in the forward direction as well as the reverse direction in the List Collection. So the ListIterator is only valid for classes such as LinkedList, ArrayList etc.The method hasNext( ) in ListIterator returns true if there are more elements in the List and false otherwise. The method next( ) returns the next element in the List and advances the cursor position.A program that demonstrates this is given as follows −Exampleimport java.util.ArrayList; import java.util.ListIterator; public class Demo { public static void main(String[] args) { ArrayList aList = new ...
Read MoreGet the count of elements in HashMap in Java
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 −Exampleimport java.util.*; public class Demo { public static void main(String args[]) { // Create a hash map HashMap hm = new HashMap(); // Put elements to ...
Read MoreGet Size of Java LinkedHashMap
The size() method is used to get the size of LinkedHashMap in Java.Create a LinkedHashMap and add some elements to it −LinkedHashMap l = new LinkedHashMap(); l.put("1", "Jack"); l.put("2", "Tom"); l.put("3", "Jimmy"); l.put("4", "Morgan"); l.put("5", "Tim"); l.put("6", "Brad");Get the size now −l.size()The following is an example to get the size of LinkedHashMap −Exampleimport java.util.LinkedHashMap; public class Demo { public static void main(String[] args) { LinkedHashMap l = new LinkedHashMap(); l.put("1", "Jack"); l.put("2", "Tom"); l.put("3", "Jimmy"); l.put("4", "Morgan"); l.put("5", "Tim"); ...
Read MoreFind the size of a HashMap in Java
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 −Exampleimport java.util.*; public class Demo { public static void main(String args[]) { // Create a hash map HashMap hm = new ...
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