An interface in Java is similar to class but, it contains only abstract methods and fields which are final and static.Just like classes you can extend one interface from another using the extends keyword as shown below −interface ArithmeticCalculations{    public abstract int addition(int a, int b);    public abstract int subtraction(int a, int b); } interface MathCalculations extends ArithmeticCalculations{    public abstract double squareRoot(int a);    public abstract double powerOf(int a, int b); }But, when you implement the sub-class you need to provide body for the abstract methods in both interfaces.ExampleIn the following example we have created two interfaces ... Read More

You can convert a character to upper case using the toUpperCase() method of the character class.ExampleFollowing program converts alternate characters of a string to Upper Case. Live Demoimport java.util.Scanner; public class UpperCase {    public static void main(String[] args) {       Scanner sc = new Scanner(System.in);       System.out.println("Enter a string :");       String str = sc.nextLine();       str = str.toLowerCase();       char[] ch = str.toCharArray();       for(int i=0; i

Following is the Java program to print diagonal pattern of a given matrix.Example Live Demopublic class DiagonalMatrix {    public static void main(String args[]){       int a[][]={{1,2,3},{4,5,6},{7,8,9}};       int rows = a.length;       int columns = a[0].length;       for (int i = 0; i < rows; i++) {          for (int r = i, c = 0; r >= 0 && c < columns; r--, c++){             System.out.print(a[r][c] + " ");          }          System.out.println();       }       for (int i = 1; i < columns; i++) {          for (int r = rows-1, c = i; r >= 0 && c < columns; r--, c++) {             System.out.print(a[r][c] + " ");          }          System.out.println();       }    } }Output1 4 2 7 5 3 8 6 9

Following is a Java program to print the spiral form of a given matrix.Example Live Demopublic class PrintMatrixInSpiralForm {    public static void main(String args[]){       int a[][]={{1,2,3},{4,5,6},{7,8,9}};       int w = 0;       int x = a.length-1;       int y = 0;       int z = a[0].length-1;       while(w

To arrange elements of the array following pendulum arrangement.Sort the given array, create an empty array to store the result.Store the 0th element in a variable say temp.Store the element at index 1 in the sorted array in (mid+1)st position of the resultant array, and the next element int the (mid-1)st position and the next element in (mid+2)nd element and so on.Example Live Demoimport java.util.Arrays; import java.util.Scanner; public class ArrayinPendulumArrangement {    public static int[] swap(int origPos, int newPos, int[] array){       origPos = 1;       newPos = 4;       int temp = array[origPos];   ... Read More

To generate a sum triangle of a given arrayGet the elements of the array from the user say, myArray[n].Create a two dimensional array say, result[n][n].Store the contents of the given array in the first row from bottom of the 2D array.result[n][i] = myArray[i].Now, from the second row of the 2D array fill elements such that ith element in each row is the sum of ith and (i+1)st elements of the previous row.result[i][j] = result[i+1][j] + result[i+1][j+1];Example Live Demoimport java.util.Scanner; public class SumTriangleOfAnArray {    public static void main(String args[]){       Scanner sc = new Scanner(System.in);       System.out.println("Enter ... Read More

Following is a Java program to find an element in an array linearly.Example Live Demoimport java.util.Scanner; public class SearchingRecursively {    public static boolean searchArray(int[] myArray, int element, int size){       if (size == 0){          return false;       }       if (myArray[size-1] == element){          return true;       }       return searchArray(myArray, element, size-1);    }    public static void main(String args[]){       System.out.println("Enter the required size of the array: ");       Scanner s = new Scanner(System.in);       int size = s.nextInt();       int myArray[] = new int [size];       System.out.println("Enter the elements of the array one by one ");       for(int i=0; i

To rotate the contents of an array cyclically −create an empty variable. (temp)save the last element of the array in it.Now, starting from the nth element of the array, replace the current element with the previous element.Store the element in temp in the 1st position.Example Live Demoimport java.util.Arrays; import java.util.Scanner; public class CyclicallyRotateanArray {    public static void main(String args[]){       Scanner sc = new Scanner(System.in);       System.out.println("Enter the required size of the array ::");       int size = sc.nextInt();       int [] myArray = new int[size];       System.out.println("Enter elements of ... Read More

To find the product of elements of an array.create an empty variable. (product)Initialize it with 1.In a loop traverse through each element (or get each element from user) multiply each element to product.Print the product.Example Live Demoimport java.util.Arrays; import java.util.Scanner; public class ProductOfArrayOfElements {    public static void main(String args[]){       System.out.println("Enter the required size of the array :: ");       Scanner s = new Scanner(System.in);       int size = s.nextInt();       int myArray[] = new int [size];       int product = 1;       System.out.println("Enter the elements of the ... Read More

Following is a Java program which prints a pyramid of numbers.Example Live Demopublic class PrintingPyramidStars {    public static void main(String args[]){       int n,i,j;       n = 5;       for(i = 0; i