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26 March 2020 7:43
Nested inner classes
Hi! Today we'll take up an important topic: how nested classes work in Java. These internal classes are called nested. They are divided into 2 types: Non-static nested classes (these are also called inner classes), Static nested classes. In turn, inner classes have two distinct subcategories...
26 March 2020 6:55
Hi! In today's lesson, we'll continue to examine the topic of nested classes. Now it's time for the last group: anonymous inner classes. Like the local classes that we talked about in the last lesson, anonymous classes are a kind of inner class... They also have several similarities and differences...
Inheritance in Java
26 March 2020 6:00
Examples of inheritance of nested classes
Hi! Today we'll look at an important mechanism: inheritance in nested classes. Have you ever thought about what you would do if you needed to make a nested class inherit some other class. If not, believe me: this situation can be confusing, because there are a lot of nuances...
24 March 2020 16:45
Enum. Practical examples. Adding constructors and methods
Hi! Today we'll talk about one of Java's special data types: Enum (short for "enumeration"). What makes it special? Let's imagine what we need to implement "months" in a program. Doesn't seem problematic, right? We just need to determine what properties that any month has. Perhaps we first need...
24 March 2020 16:19
Java's Comparator class
Hi! Today we're going to talk about comparing objects. Hmm... But haven't we already talked this topic more than once? :/ We know how the == operator works, as well as the equals() and hashCode() methods. Comparison is a little different. Previously, we most likely meant "checking objects for equality"...
23 March 2020 18:04
Your first application using Java servlets
Hello, everyone! You will become familiar with servlets as a basic concept of web development, and you will be able to write a simple application that uses them. To avoid unnecessary actions, we won't start from scratch. We'll continue working on our application from my previous article about Hibernate...
23 March 2020 13:58
Your first Hibernate application
In this article, you will become familiar with one of the most popular enterprise frameworks for Java and create your first Hibernate application. Never heard of Hibernate? Or maybe you've heard of it, but haven't used it? Or maybe you tried to use it, but failed? In all three cases - welcome to below the cut :)
23 March 2020 12:29
Tricky Java questions frequently asked at interviews
If you've ever prepared for an interview for a Java programmer position or passed any certification exam (not necessarily about programming), then you've probably already noticed that the questions asked there are very specific. Many of them force you think about the language's design. Some are designed to probe...
16 March 2020 14:09
Debugging in IntelliJ IDEA: a beginner's guide
Hello everyone in the CodeGym community! Today let's talk about debugging — what is it and how to debug in IntelliJ IDEA. This article is intended for people who already have a minimum knowledge of Java Core. There won't be any frameworks or complicated procedures to publish libraries. A leisurely stroll...
Serialization in Java
11 March 2020 13:21
What is the difference between serialization and deserialization in Java?
Hi! In today's lesson, we talk about serialization and deserialization in Java. We'll start with a simple example. Let's say you've created a computer game. If you grew up in the 90s and remember the game consoles of that era, you...
11 March 2020 10:35
From NASA to the deserts of Africa. Government-sponsored and socially-significant projects written in Java
Today we will talk about how Java is used by government agencies and in socially-significant projects around the world. Austria is well-known for its state-of-the-art and convenient social security system, which includes excellent health...
11 March 2020 9:14
Junior Java developer looking for work. How to upgrade your skills and gain practical experience
When speaking of the beginning of a Java programmer's professional career, everything is often presented in a gloomy light. To beginners, it may seem that breaking into the market is incredibly difficult. No matter how many current job...
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