You can read the contents of a file using the Scanner class and You can find the comments in a particular line using contains() method.Exampleimport java.io.*; import java.util.Scanner; public class FindingComments {    public static void main(String[] args) throws IOException {       Scanner sc = new Scanner(new File("HelloWorld"));       String input;       int single = 0;       int multiLine = 0;       while (sc.hasNextLine()) {          input = sc.nextLine();          if (input.contains("/*")) {             multiLine ++;       ... Read More

To verify whether the given string is a palindrome (using arrays) Convert the given string into a character array using the toCharArray() method. Make a copy of this array. Reverse the array. Compare the original array and the reversed array. in case of match given string is a palindrome. Example import java.util.Arrays; import java.util.Scanner; public class Palindrome { public static void main(String args[]) { System.out.println("Enter a string "); Scanner sc = new Scanner(System.in); String s ... Read More

To delete an element at a particular position from an array. Starting from the required position, replace the element in the current position with the element in the next position.Example Live Demopublic class DeletingElementsBySwapping { public static void main(String args[]) { int [] myArray = {23, 93, 56, 92, 39}; System.out.println("hello"); int size = myArray.length; int pos = 2; for (int i = pos; i

Stack is an Abstract Data Type (ADT), commonly used in most programming languages. It is named stack as it behaves like a real-world stack, for example – a deck of cards or a pile of plates, etc.A stack is first in first out, it has two main operations push and pop. Push inserts data in to it and pop retrieves data from it.To reverse an array using stack initially push all elements in to the stack using the push() method then, retrieve them back using the pop() method into another array.ExampleLive Demoimport java.util.Arrays; import java.util.Stack; public class ReversinArrayUsingStack { ... Read More

Apache commons provides a library named org.apache.commons.lang3 and, following is the maven dependency to add library to your project.           org.apache.commons       commons-lang3       3.0     This package provides a class named ArrayUtils. You can add an element at a particular position in an array using the add() method of this class.Exampleimport java.util.Arrays; import org.apache.commons.lang3.ArrayUtils; public class AddingElementToMidPoint {    public static void main(String args[]) {       int[] myArray = {23, 93, 30, 56, 92, 39};       int eleToAdd = 40;       int position= myArray.length/2;       int [] result = ArrayUtils.add(myArray, position, eleToAdd);       System.out.println(Arrays.toString(result));    } }Output[23, 93, 30, 40, 56, 92, 39]

A linked list is a sequence of data structures, which are connected together via links.To create an array of linked lists, create required linked lists and, create an array of objects with them.ExampleLive Demoimport java.util.LinkedList; public class ArrayOfLinkedList {    public static void main(String args[]) {       LinkedList list1 = new LinkedList();       list1.add("JavaFX");       list1.add("Hbase");             LinkedList list2 = new LinkedList();       list2.add("OpenCV");       list2.add("Mahout");             LinkedList list3 = new LinkedList();       list3.add("WebGL");       list3.add("CoffeeScript");       Object[] obj = {list1, list2, list3};             for (int i=0; i

In the loop check, the result of i%2 operation on each element if 0 the element is even else the element is odd.ExampleLive Demopublic class OddNumbersInAnArray {    public static void main(String args[]) {       int[] myArray = {23, 93, 56, 92, 39};       System.out.println("Even numbers in the given array are:: ");       for (int i=0; i

An array is a data structure/container/object that stores a fixed-size sequential collection of elements of the same type. The size/length of the array is determined at the time of creation. The position of the elements in the array is called as index or subscript. The first element of the array is stored at the index 0 and, the second element is at the index 1 and so on. Each element in an array is accessed using an expression which contains the name of the array followed by the index of the required element in square brackets. You can access an ... Read More

To convert an object to byte arrayMake the required object serializable by implementing the Serializable interface.Create a ByteArrayOutputStream object.Create an ObjectOutputStream object by passing the ByteArrayOutputStream object created in the previous step.Write the contents of the object to the output stream using the writeObject() method of the ObjectOutputStream class.Flush the contents to the stream using the flush() method.Finally, convert the contents of the ByteArrayOutputStream to a byte array using the toByteArray() method.Exampleimport java.io.ByteArrayOutputStream; import java.io.ObjectOutputStream; import java.io.Serializable; class Sample implements Serializable {    public void display() {       System.out.println("This is a sample class");    } } public ... Read More

To move an element from one position to other (swap) you need to –Create a temp variable and assign the value of the original position to it.Now, assign the value in the new position to original position.Finally, assign the value in the temp to the new position.ExampleLive Demoimport java.util.Arrays; public class ChangingPositions {    public static void main(String args[]) {       int originalPosition = 1;       int newPosition = 4;       int [] myArray = {23, 93, 56, 92, 39};       int temp = myArray[originalPosition];       myArray[originalPosition] = myArray[newPosition];       myArray[newPosition] = temp;       System.out.println(Arrays.toString(myArray));    } }Output[23, 39, 56, 92, 93]