Does Java have default parameters?

Short answer: No.

Fortunately, you can simulate them.

Many programming languages like C++ or modern JavaScript have a simple option to call a function without providing values for its arguments. In Java, default method parameters require a bit more typing to achieve this effect in comparison to other languages. From this article, you will learn how the default method parameters work in Java.

Continue reading “Does Java have default parameters?”

Understanding JavaScript Promise

The JavaScript Promise is a concept that every modern self-respecting web developer should be familiar with. No matter if you just started learning JavaScript or trying to catch up on the JavaScript language updates. If you want to understand the JavaScript Promise, this article is for you.

I will quickly take you through the theory of Promises and jump right into its API with practical usage examples. After reading, you will be ready to work with Promises created by JavaScript frameworks but also know how to create your own.

Enough of the introduction. Let’s get this show on the road.
Continue reading “Understanding JavaScript Promise”

What is Spring bean?

In short, a Spring bean is an object which Spring framework manages at runtime. A Spring bean is a basic building block of any Spring application. Most of the application logic code you write will be placed in Spring beans.

The management of a Spring bean includes:

  • creating an object
  • providing dependencies (e.g. other beans, configuration properties)
  • intercepting object method calls to provide additional framework features
  • destroying an object

A Spring bean is a fundamental concept of the framework. As a user of Spring, you should have a deep understanding of this core abstraction.

Keep reading and you’ll find out all you need to know about Spring beans.
Continue reading “What is Spring bean?”

Injecting Spring Prototype bean into Singleton bean

Have you ever wonder why singleton is the default scope for Spring beans? Why isn’t it prototype?

It’s not a random choice. It’s because the vast majority of business logic we create can be safely kept in stateless objects. And the best choice for stateless beans is the singleton scope. The prototype scope is better for stateful beans to avoid multithreading issues.

Yet, sometimes you need to mix both and use a prototype bean in a singleton bean. This particular case is a bit tricky. In this article, I’m going to explain to you different ways of accessing prototypes in singletons.

So let’s begin.

Continue reading “Injecting Spring Prototype bean into Singleton bean”

How to bind @RequestParam to object in Spring

Do you have multiple parameters annotated with @RequestParam in a request mapping method and feel it isn’t readable?

The annotation looks pretty straightforward when there’s one or two input parameters expected in a request but when the list gets longer you might feel overwhelmed.

You cannot use the @RequestParam annotation inside objects but it doesn’t mean you’re left with no other solution. In this post, I’m going to show you how to bind multiple request parameters to an object in Spring application.

Continue reading “How to bind @RequestParam to object in Spring”

The JavaScript runtime environment

Have you just started learning JavaScript?

Or maybe you already have some language experience but want to understand JavaScript runtime in more details?

Whatever reason brought you here, there are a few elements of JavaScript runtime that you should get to know.

In this article, I’m going to show you how the JavaScript runtime environment works under the hood. You’ll learn about its elements, their responsibilities, and the way they interact with each other.

Are you ready?

If so, let’s start with the first element of the puzzle.

Continue reading “The JavaScript runtime environment”

Spring Boot file

Spring Boot comes with a built-in mechanism for application configuration using a file called In this article, I’ll show you how to effectively use the file in custom scenarios.

I’m not going to discuss properties specified by the Spring Boot framework. Working with existing configuration keys is pretty straightforward. You can easily find common keys in the official documentation.

This post covers defining custom properties, handling data types, and working with properties on different runtime environments. If that’s what you’re looking for, keep on reading.

Continue reading “Spring Boot file”

Spring Custom Validator by example

Since you’re here, you probably reach the point in which standard annotations like @NotNull or @Size don’t meet your expectations. Fortunately, I have good news for you. Creating a custom validation annotation is pretty easy. In this post, you will learn how to create a custom constraint annotation and a corresponding validator class. You will also see how to use Spring beans inside a custom validator.

Let’s just right into it.

Continue reading “Spring Custom Validator by example”