HashMap<K, V> map = new HashMap<>(); Map<Integer, String> map = new HashMap<>(); class Test { public static void main(String[] args) { Map<Integer, String> map = new HashMap<>(); map.put(1, “Java”); map.put(7, “Python”); map.put(10, “Ruby”); map.put(3, “Kotlin”); System.out.println(map); } } Output: {1=Java, 3=Kotlin, 7=Python, 10=Ruby} class Test { public static void main(String[] args) { Map<Integer, String> map…
Read More Map in JavaHashSet<String> set = new HashSet<>(); Set<String> set = new HashSet<>(); class Test { public static void main(String[] args) { Set<String> set = new HashSet<>(); set.add(“Java”); set.add(“Kotlin”); set.add(“Python”); set.add(“Ruby”); System.out.println(set); } } Output: [Java, Ruby, Kotlin, Python] class Test { public static void main(String[] args) { Set<String> set = new HashSet<>(); set.add(“Kotlin”); set.add(“Java”); set.add(“Ruby”); set.add(“Python”); Set<String>…
Read More Set in JavaLinkedList<String> list = new LinkedList<>(); List<Integer> list = new LinkedList<>(); class Test { public static void main(String[] args) { List<String> list = new LinkedList<>(); list.add(“Steve”); list.add(“Megan”); list.add(“Melissa”); list.add(“Ryan”); System.out.println(list); } } Output: [Steve, Megan, Melissa, Ryan] class Test { public static void main(String[] args) { List<String> list = new LinkedList<>(); list.add(“Steve”); list.add(“Megan”); list.add(“Melissa”); list.add(“Ryan”); List<String>…
Read More LinkedList in JavaArrayList<String> list = new ArrayList<>(); List<Integer> list = new ArrayList<>(); class Test { public static void main(String[] args) { List<String> list = new ArrayList<>(); list.add(“Steve”); list.add(“Megan”); list.add(“Melissa”); list.add(“Ryan”); System.out.println(list); } } Output: [Steve, Megan, Melissa, Ryan] Using the addAll() method, we can add all the elements of an existing list to the newly created…
Read More ArrayList in JavaIterator<T> iterator() Method Description public boolean add(E e) It is used to insert an element in this collection. public boolean addAll(Collection<? extends E> c) It is used to insert the specified collection elements in the invoking collection. public boolean remove(Object element) It is used to delete an element from the collection.…
Read More Java Collectionsclass Test { public static void main(String[] args) { for (int i = 0; i < 10; i++) { System.out.println(“Value:” + i); if (i == 3) { break; // terminate the loop if condition is met } } System.out.println(“Code after the loop…”); } } Output: Value:0 Value:1 Value:2 Value:3 Code after the loop… In…
Read More Java break and continue statementsIn Java, there are three main types of loops: while loops, do-while loops, and for loops. These loop structures are similar in many ways, but they differ in some key aspects that make them useful for different scenarios. This tutorial will introduce you to the concepts and syntax behind Java while and do-while loops. You…
Read More ‘while’ and ‘do-while’ Loops: The Secret to Efficient Java ProgrammingFor loops are an important part of Java programming and are used to execute a block of code repeatedly. They are especially useful when working with arrays or collections, allowing you to easily access and manipulate each element in the array or collection. In this tutorial, you will learn about the syntax of a for…
Read More Java For Loops: A Comprehensive Guideswitch (expression) { case constant: // switch block 1… break; case constant: // switch block 2… break; default: // default switch block … ; } class Test { public static void main(String[] args) { String color = “blue”; switch (color) { case “white”: // if it is white, execute this block of code System.out.println(“The color…
Read More Java switch Statementclass Test { public static void main(String[] args) { int a = 10; int b = 5; if (a > b) { // if true, enter the if code block System.out.println(“a is greater than b”); } System.out.println(“Rest of the code …”); } } Output: a is greater than b Rest of the code … …
Read More Java if-else Statementclass Test { public static void main(String[] args) { String str = “ALEGRUTECHBLOG”; String strInLowerCase = str.toLowerCase(); System.out.println(strInLowerCase); } } Output: alegrutechblog toUpperCase() Converts all of the characters in this String to the upper case using the rules of the default locale. class Test { public static void main(String[] args) { String str…
Read More Working With Strings in Java – Part 2class Test { public static void main(String[] args) { String str = “alegru”; char c = str.charAt(2); System.out.println(c); } } Output: e class Test { public static void main(String[] args) { String str = “alegru”; int index = str.indexOf(‘l’); System.out.println(index); } } Output: 1 class Test { public static void main(String[] args) { String str…
Read More Working With Strings in Java – Part 1Java Strings are one of the most commonly used data types in Java programming, and understanding how to work with them effectively is essential for any Java developer. In this tutorial, I will cover everything you need to know about Java Strings, from the basics of creating and manipulating Strings to advanced concepts like regular…
Read More Mastering Java String: A Comprehensive Tutorialimport java.util.Arrays; class Test { public static void main(String[] args) { String[] names = {“John”, “Steve”, “Melissa”, “Maria”}; System.out.println(Arrays.toString(names)); } } Output: [John, Steve, Melissa, Maria] copyOf(type [] a, int n) Returns a new copy of the array, which consists of the first n of its elements. import java.util.Arrays; class Test { public static…
Read More Arrays class in JavaDeclaring a multidimensional array in Java class Test { int[][] array1; int[][] array2; int array3[][]; } class Test { int[][] array1 = new int[3][3]; // 3 rows and 3 columns int[][] array2 = {{1, 2}, {3, 4}}; // 2 rows and 2 columns } class Test { public static void main(String[] args) { int[][] array…
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