To generate two separate outputs, at first create a new Random object −private static final Random r = new Random();Now, let us declare a value −int val = 5;Loop from the value till 100 and generate random numbers between 1 to 100 −while (val<= 100) {    System.out.printf("%-4d", r.nextInt(20) * ... Read More

Let us first declare a string array and initialize −String[] strArr = { "P", "Q", "R", "S", "T", "U", "V", "W" };Now, create a Random object −Random rand = new Random();Generate random string −int res = rand.nextInt(strArr.length);Example Live Demoimport java.util.Random; public class Demo {    public static void main(String[] args) { ... Read More

To generate random values that won’t repeat, use HashSet collection. Firstly, create a random object and HashSet −Random randNum = new Random(); Set<Integer>s = new HashSet<Integer>();Now, add random integers −while (s.size() < 10) {    s.add(randNum.nextInt()); }Now, display the random numbers that are unique −List<Integer>list = new ArrayList<Integer>(s); System.out.println(list);Example Live Demoimport ... Read More

At first, create a character array −static char num[] = { '0', '1', '2', '3', '4', '5' };Now, let’s say you want to a string with length. Create a StringBuilder and use append() to create random numbers string out of it −int len = 5; StringBuilder strBuilder = new StringBuilder(); ... Read More

To convert integer array list to float array, let us first create an integer array list −ArrayList < Integer > arrList = new ArrayList < Integer > (); arrList.add(25); arrList.add(50); arrList.add(100); arrList.add(200); arrList.add(300); arrList.add(400); arrList.add(500);Now, convert integer array list to float array. We have first set the size to the ... Read More

To generate a random number, create a Random object and use nextInt(). The same works for array as well.Let us first create an array and add elements −int[] arr = new int[] { 10, 30, 45, 60, 78, 99, 120, 140, 180, 200};Now, get a random number from array by ... Read More

To generate random BigInteger in Java, let us first set a min and max value −BigInteger maxLimit = new BigInteger("5000000000000"); BigInteger minLimit = new BigInteger("25000000000");Now, subtract the min and max −BigInteger bigInteger = maxLimit.subtract(minLimit); Declare a Random object and find the length of the maxLimit: Random randNum = new Random(); ... Read More

To generate custom random number 1 or -1, you need to use nextBoolean(). At first take a loop and create a Random object on each iteration −for (int i = 0; i < 5; i++) {    Random rand = new Random(); }Now, use nextBoolean() to generate 1 on TRUE ... Read More

To generated random integer, use the Random class with nextInt. At first, create a Random object −Random rand = new Random();The Random above is a random number generator. Now, pick the random numbers one by one. We want 10 random four-digit numbers, therefore loop it until i = 1 to ... Read More

Let us first create an ArrayList −ArrayList<String>arr = new ArrayList<String>(); arr.add("50"); arr.add("100"); arr.add("150"); arr.add("200"); arr.add("250"); arr.add("300");Now, let’s say we have another Collection as Vector −Vector<String>vector = new Vector<String>(); vector.add("500"); vector.add("700"); vector.add("800"); vector.add("1000"); Append all the elements from the Vector to ArrayList: arr.addAll(vector);Example Live Demoimport java.util.ArrayList; import java.util.Vector; public class Demo { ... Read More

Let us first create an ArrayList −ArrayList < Integer > arrList = new ArrayList < Integer > (); arrList.add(100); arrList.add(200); arrList.add(300); arrList.add(400); arrList.add(500);Now, create a ListIterator from the above ArrayList and insert more elements −ListIterator < Integer > iterator = arrList.listIterator(); iterator.add(1000); iterator.add(2000); iterator.add(3000);Example Live Demoimport java.util.ArrayList; import java.util.ListIterator; public class ... Read More

Let us first create an ArrayList −ArrayList<Integer>arrList = new ArrayList<Integer>(); arrList.add(10); arrList.add(50); arrList.add(100); arrList.add(150); arrList.add(250);Use Comparators interface to order in reverse order with reverseOrder() −Comparator comparator = Collections.reverseOrder(); Now, sort with Collections: Collections.sort(arrList, comparator);Example Live Demoimport java.util.ArrayList; import java.util.Collections; import java.util.Comparator; public class Demo {    public static void main(String[] args) ... Read More

Let us first set the LocalDate to current date −LocalDate date = LocalDate.now();Create an Instant −Instant i = date.atStartOfDay().atZone(ZoneId.systemDefault()).toInstant();Convert it to java.util.Date −java.util.Date.from(i)Example Live Demoimport java.time.Instant; import java.time.LocalDate; import java.time.ZoneId; public class Demo {    public static void main(String[] args) {       LocalDate date = LocalDate.now();       ... Read More

Set the LocalDateTime to current datetime −LocalDateTime dateTime = LocalDateTime.now();Create an Instant −Instant i = dateTime.atZone(ZoneId.systemDefault()).toInstant(); Convert LocalDateTime to java.util.Date: java.util.Date date = Date.from(i);Example Live Demoimport java.time.Instant; import java.time.LocalDateTime; import java.time.ZoneId; import java.util.Date; public class Demo {    public static void main(String[] args) {       LocalDateTime dateTime = LocalDateTime.now(); ... Read More

We have considered a number 10 here, which will divided into 8 random ints with Random class. The number we have set as HashSet collection −HashSet<Integer>set = new HashSet<Integer>(); set.add(0); set.add(0); set.add(0); set.add(number);Now use nextInt to get the next random integer −intarrSize = parts + 1; while (set.size() < arrSize) ... Read More