Reversing a string is a common task in Java programming, and there are several ways to accomplish this. In this tutorial, we’ll explore four different methods for reversing a string in Java, using the StringBuilder class, the for loop, recursion, and a character array. We’ll provide examples of each method and explain how they work.…
Read More Reverse a String in Javapublic int sum(int a, int b, int c) { // body of the method } class Printer { // fields public void printBook(String bookName) { // … } public void printBook(String bookName, int numberOfPages) { // … } } class Printer { // fields public void printBook(String bookName) { // … } public String printBook(String…
Read More Method Overloading in JavaWorking with strings is a fundamental aspect of programming, and Java provides a rich set of tools and methods for manipulating strings. One common task when working with strings is to remove whitespace characters such as spaces, tabs, and newlines. There are several ways to accomplish this in Java, including using the replaceAll() method from…
Read More Removing Whitespaces in Java StringsIn this lesson, you will learn about the history of Java, types of Java programs, Java Virtual Machine (JVM), Java Standard Library and current Java editions. History Java was developed in 1991 by the Green Team, comprising James Gosling, Mike Sheridan, and Patrick Naughton, as a pilot project for a simple language to program smart…
Read More Introduction to JavaOutput: Brand is: Ford This is a Ford with a number of seats 5 and with colour blue
Read More Java Inheritance: A Beginner’s GuideIn this tutorial, we will explore how to use the Java HttpClient to upload a file to the server. In the next tutorial, we will cover how to configure HttpClient to accept all SSL certificates. Let’s get started! In the code example below, we will use the Apache HttpClient and the MultipartEntityBuilder. HttpClient Maven Dependencies…
Read More Java File Upload using HttpClientConvert char to String in Java using the String.valueOf() method There is a valueOf() static method in the String class that returns the String representation of its argument, which can be a char or any other data type. public class Test { public static void main(String[] args) { char ch = ‘a’; String str =…
Read More Convert Char to String in JavaIn this Java tutorial, I am going to share with you different ways how to generate a random string of characters. You will learn to generate the following types of random Strings of characters: alpha-numeric String of characters of any length or of a specific length, Letters only, Numbers only. I hope you will find…
Read More Random String of Characters in Java. Different Examples.In this tutorial, we will generate a random alpha-numeric string of characters, which can be used as a user password. Password Requirements When generating passwords, it’s important to set requirements that make them strong and difficult to guess. Here are some guidelines to follow when creating password requirements: Length The length of a password is…
Read More Generate Secure Password in JavaIn this blog post, I will share how to copy properties from a DTO object to an Entity object and then back from an Entity object to a DTO object. DTO stands for Data Transfer Object, and it is a simple, Plain Old Java Object that typically contains class properties and getter and setter methods…
Read More DTO to Entity Conversion in JavaMockito enables partial mocking of an object, allowing us to create a mock object while still invoking a real method. To achieve this, we can use Mockito’s thenCallRealMethod() method to call a real method on a mocked object. I have also created several step-by-step video lessons that demonstrate how to test Java applications. If you…
Read More Mockito – Call a Real MethodIn this tutorial, you will learn how to write a JUnit test that validates whether the method under test throws the correct exception. The tutorial includes examples for both JUnit 5 and JUnit 4. For video lessons, check out my video course: Testing Java with JUnit and Mockito. Let’s begin with JUnit 5 version first.…
Read More Test for Exception in JUnit 5 and JUnit 4In this tutorial, I am going to share with you a few different techniques you can use to iterate over a collection in Java. Iterating ArrayList with Enhanced For-Loop List<String> names = new ArrayList<>(); names.add(“Sergey”); names.add(“Bill”); names.add(“John”); for(String name: names) { System.out.println(name); } Output: Sergey Bill John We declare a List of String objects named…
Read More Iterating over Collections in Java: ExamplesOptional<T> findFirst() class Test { public static void main(String[] args) { List<Integer> numbers = new ArrayList<>(Arrays.asList(3, 7, 9, 12)); Optional<Integer> resultOptional = numbers.stream().findFirst(); if (resultOptional.isPresent()) { // checking if Optional contains any value System.out.println(“The first element in the stream is: ” + resultOptional.get()); // getting the value from Optional } else { System.out.println(“The stream is…
Read More Streams – findFirst() operationLearning how to convert Java objects into JSON and vice versa can be very helpful for your work as a full-stack mobile app developer. In this blog post, I will share some code examples that will help you with the most common tasks you’ll encounter when working with JSON and Java. I will cover the…
Read More Convert Java into JSON and JSON into Java. All Possible Examples.