Lessons

In this level, you continued to get acquainted with collections: you figured out what HashMap and TreeMap are, and also learned more about the methods of the Collections helper class.

History of LinkedList. Java has another interesting operator that it inherited from its grandpappy (C++). This is the LinkedList class, which implements a "linked list". Outwardly, a LinkedList appears to be the same as an ArrayList. The LinkedList class has all the same methods as the ArrayList class. In principle...

For most people, the word "queue" brings to mind very few pleasant associations. But today we're talking about different queues — Java queues. In Java, a queue is anything that inherits the Queue interface, which in turn extends the Collection interface...

In this lesson, we'll study the SortedMap interface. We'll explore new methods that appear in this interface, as well as the features of one implementation of SortedMap — TreeMap — and the differences between implementations...

In this level, you continued to get acquainted with collections: you figured out what LinkedList and Queue are, and also learned about the SortedMap interface.

Background on how enum came to be. Today we will explore another kind of data type in Java: enum. The name enum comes from the word enumeration. What is this data type and what's it for? Sometimes a programmer needs to create a new data type, whose possible values...

Perhaps you've heard that Singleton single malt Scotch whisky is good? Well, alcohol is bad for your health, so today we will tell you about the singleton design pattern in Java instead...

You recently delved into the singleton design pattern, how to implement it in Java, and what it is for. But what if I tell you that Java comes with its own singleton out of the box? Intrigued? Then let's dive in...

The multiple-choice operator: switch. Java has another interesting operator that it inherited from its grandpappy (C++). We're talking about the switch statement. We could also call it a multiple-choice operator. It looks a little cumbersome: switch(expression) { case value1: code1;...

Enum, switch... did we forget anything?

The job of a programmer. Very often novice programmers think of the work of a programmer completely differently than how experienced programmers think of it. Beginners often saying something like "The program works, what else do you need?" An experienced programmer knows that "works correctly" is only one of the require...

Exceptions. At long last, programmers thought to standardize and automate error handling. This happened when exceptions were invented. Now the exception mechanism handles 80% of exceptional situations. If some scholar came up with exceptions, it was likely the subject...