Lessons

We need Java and other languages to facilitate communication between people and computers. Handling even simple actions utilizes critical computer components such as peripherals, the input/output subsystem, CPU, and memory. This video explains the steps your computer takes every time you click with the mouse.

Captain Squirrels is on the phone! He has a couple of surprises for you. More precisely, not a couple, and they aren't surprises, but rather ten tasks to reinforce your knowledge about threads. And the truly curious can try their hand on three bonus tasks that are more difficult. For example, in one of them you'll deal with an unlucky waiter in a restaurant.

Congratulations, you've completed the seventh level of the quest! It truly was difficult. You have continued to get acquainted with threads, and begun to handle problems related to multithreading. You've completed 23 tasks (or about that many). Continuing in that same spirit, we'll take a closer look at input/output streams.

In fact, you already know something about I/O streams. Remember System.out.println? Guess what? System.out is a static PrintStream (a descendant of OutputStream) variable in the System class. So all this time you've been happily using a PrintStream.

In this lesson, your teacher Rishi will tell you about two classes for reading and writing files. They are FileInputStream and FileOutputStream. As you probably already guessed, the first lets you sequentially read bytes from a file; with the second, you can sequentially write bytes to a file. Click on the lesson, and you'll learn how these classes are organized.

You never know whether you understand a topic until you've tried to apply your knowledge in practice! Diego knows this well. So today he has prepared five tasks for you to practice using the FileInputStream and FileOutputStream classes. We'll look for and display the minimum, maximum, most frequent, and rarest bytes in a file.

Today, your teacher Ellie will help you to better understand the nature of InputStream and OutputStream. You'll learn that these two are not interfaces at all: they're abstract classes. They even have a couple of implemented methods. Which? Find out in this lesson.

Diego, a robot and skilled teacher, believes that students on Level 8 of the second quest don't study enough. What's more, it's crunch time right now! So, there's no time to cool off. You're being pushed to complete tasks on the "Taming of InputStream and OutputStream in the wild".

Have you noticed how many complicated compound words Java has? Today's lesson is devoted to the elegantly named BufferedInputStream class. But first, your teacher Kim will tell you about the wrapper design pattern and why it is needed.

Today we'll explore some super interesting stuff: how to replace the System.in input stream. First, we need to create a buffer, and then put some values into it. Then we'll wrap it in a class that knows how to read data from the buffer using the InputStream protocol. The details are in the lesson.

If you've enjoyed learning about streams, all these wrappers, and BufferedInputStream, you'll take pleasure in completing these five tasks, which have been prepared for you by Diego the Magnificent. And if you haven't liked the topic... Well, you'll complete them without pleasure. How can you escape it?

Of course, looking at the same material from different angles is useful, because everyone thinks differently, and perhaps for you the best source of the theory will be different from the source best suited to your friend. Especially for you, the Professor found a very interesting lesson online that will teach you a lot more about input/output streams.