Lessons

You’ve almost completed Level 8! With all these lectures and tasks, you need a break. Learning Java may be tough, but remember: the world can’t exist without Java! What if it suddenly disappeared one day? What would happen to our familiar surroundings? Make yourself comfortable and watch an exciting and fun video about the real Javapocalypse. :)

In life, do you often misunderstand what others want from you? Alas, this can happen with any work, even programming: a developer's job is sometimes assigned by someone who isn't too familiar with the features of the work of the person writing the code. Some of the task conditions may seem incomprehensible, or maybe everything is clear from the outset?

College education has led us to think that there are no fundamental differences between theory and practice. No, of course you realize the two are not the same. Still, you don't see any critical difference. However, it does exist. Most people equate "I know" with "I can". Do you ever do that? Consider the following...

An object is a variable whose type is a class. Or an instance of a class, if you like. This means that an object is created just like any new variable, or more precisely, like any reference variable. This lesson will teach you the syntax for creating objects, and give you your first exposure to special and super useful methods known as getters and setters.

At the secret CodeGym center, you'll practice on cats and dogs all over the place. But animal-rights advocates can be calm: No animal used as an object has been harmed during this practice. We have already dealt with the theory of creating classes and objects. It's time to do some tasks, get used to the syntax, and make sure it's right.

Initialization is basically initiation into the world of objects! Someday (in fact, very soon, if you don't quit) you'll learn what encapsulation is and why it is needed. Meanwhile, we'll take our first step toward it by learning what it means to initialize objects and why we need to do it.

When an object is created, you have to assign initial data to its variables. This prevents situations where you might access an object that doesn't have the internal information it needs to work properly. Let's complete some initialization tasks: we'll begin by creating valid cats, dogs, friends, and other objects.

Some people think programmers are like construction workers who erect buildings. There's something to this analogy. But today we're going to talk about a different kind of constructor. Since all objects must be initialized one way or another, special abbreviated initializers were invented to perform this process. They are called constructors.

You won't find a constructor wearing a hard hat at a construction site. It's a special method for initializing objects. It's where you write initial values for an object's fields (though not necessarily all of them). A constructor has the same name as the class. One class can have many constructors. Or just one...known as the default constructor. We'll master all this through practice.

In past lessons, you learned more about what a typical Java program is and what its design looks like. How objects are created (and what this has to do with constructors) and how variables are initialized. Brace yourself: there will be a lot of extra reading this time. But...

You don’t have to unplug your brain to prevent a meltdown due to an overabundance of new information. We just need to feed it something simple that’s still interesting. Let’s watch an inspiring speech by Larry Smith about why people fail to have great careers unless they follow their passion and see opportunities instead of obstacles.

There's no such thing as extra tasks in the study of programming! The professor at the secret CodeGym center is 1000% convinced of this. That's why several tasks must be completed at the end of the level. Some of them are more advanced and require student's to be able to google. Or think. Or think and google.