In 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 JavaJava provides a lot of built-in methods for manipulating strings. These methods make it easy to perform common string operations like concatenation, splitting, and searching. To find more code examples that demonstrate how to work with Strings in Java, check out the following tutorials: Java String Working With Strings in Java – Part 1 Working…
Read More Java String Methods Every Developer Should KnowA test suite is a collection of test cases that are run together as a single unit. It helps to organize and manage the execution of multiple test cases. Test suites can be used to group related tests or to test different aspects of a complex system. They can also be used to run tests…
Read More JUnit 5 Test Suite TutorialThis tutorial will teach you how to use project Lombok in the Spring Boot application. Overview No doubt Java is a wonderful language, but one of the drawbacks of Java is its verbose nature. This makes it fairly complicated for everyday tasks such as composing a simple POJO object. For example, constructing of methods like Getters(), Setters(),…
Read More How to use Project Lombok in Spring BootThis tutorial will teach you how to add Spring Security to your project and enable in-memory basic authentication. You will learn how to configure two different users with different Roles and Privileges. Both users’ roles and privileges will be stored in the memory of your Spring Boot application. If you use Spring Framework and OAuth,…
Read More Spring Security In-Memory AuthenticationIntroduction Linked lists are an important data structure used in programming. They are especially useful when the size of the data is unknown and dynamic, or when we want to implement other data structures like stacks and queues. In this tutorial, we’ll focus on singly linked lists (SLL), one of the most commonly used linked…
Read More Singly linked list in JavaIn the world of testing, mock objects are used to simulate the behavior of real objects in the application. Mockito is a popular framework for creating mock objects in Java. A Spy in Mockito is a type of mock object that allows you to create a partial mock of an object by spying on an…
Read More Mockito Spy Explained: A Comprehensive GuideMockito 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 MethodI often find myself needing to run a single unit test for a particular project from the command line in my terminal window, rather than all of the tests. In this blog post, I’ll show you how to do just that: run a specific unit test using Maven from the command line. For video tutorials…
Read More Running a Single Unit Test with MavenIn this article, you will learn how to perform user authentication with Amazon Cognito in a Spring Boot application. But before we dive into that, let’s first explore what Amazon Cognito is. According to what’s mentioned on the AWS official website: Amazon Cognito lets you add user sign-up, sign-in, and access control to your web…
Read More User Authentication with Amazon Cognito in Spring Boot ApplicationIn 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 4Introduction A Doubly Linked List (DLL) is a data structure in which each node of the list contains a pointer to its previous and next nodes. This allows bidirectional traversal of the list. In this tutorial, we will discuss the representation, advantages, and disadvantages of using a DLL over a singly linked list, operations on…
Read More Doubly Linked List in JavaIn 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() operationThis tutorial examines various methods for checking if a key exists in a Python dictionary. A dictionary in Python is an unordered collection of data values that serve as a mapping mechanism for storing and managing values. It consists of key-value pairs, where values are retrieved based on their corresponding keys. Dictionaries are widely used…
Read More Check if a Key exists in a Python dictionary