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 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.In the previous lesson, we covered the conversion of a Decimal to Binary. Here, you will learn how to convert Binary to Decimal in Java. There are a couple of ways: Using the parseInt() method With custom logic Convert Binary to Decimal in Java using the parseInt() method We can use the parseInt(String s, int…
Read More Convert Binary to Decimal in JavaFunction<String, String> modifyString = (name) -> name.toUppecCase().concat(“modified”);
Read More Introduction to Java Functional ProgrammingMethods are an essential part of Java programming. They are used to group a set of statements together to perform a specific task, which can be called whenever needed. In this tutorial, we will discuss the different types of methods in Java, including predefined methods and user-defined methods, and their advantages. We will also cover…
Read More Master Methods in JavaThe Java Virtual Machine (JVM) is an integral part of the Java platform and is responsible for executing Java code. It provides a platform-independent environment for running Java applications, allowing developers to write code once and run it anywhere. Understanding how the JVM works is essential for Java developers to optimize performance and ensure the…
Read More Java Virtual Machine (JVM): The Complete GuideVariables are an essential part of programming in Java. They are used to store data that can be later retrieved and manipulated. Understanding the different types of variables and their scope is crucial to writing efficient and maintainable code. In this tutorial, we will discuss the basics of variables in Java, including what they are,…
Read More Master Variables in JavaIn addition to the Java Runtime Environment (JRE), the JDK includes the following components: Compiler The Java compiler is used to convert Java source code into bytecode that can be executed on the Java Virtual Machine (JVM). A compiler is a command-line tool that takes a .java file as input and produces a .class file…
Read More JRE, JDK, and JVM: Understanding Differences and UsesPrimitive type Wrapper class boolean Boolean byte Byte char Character float Float int Integer long Long short Short double Double class Test { int id = 5; Integer id1 = id; // autoboxing } class Test { public static void main(String[] args) { int a = 10; int b = 20; List<Integer> list = new…
Read More Autoboxing and Unboxing in JavaProgramming languages like Java rely on the use of data types to manage and manipulate data in a program. Data types are a fundamental concept in programming and understanding them is crucial to becoming a proficient Java developer. Java has two main categories of data types: primitive data types and reference data types. Primitive data…
Read More Java Data Types: The Complete Beginner’s Guide