Print

Welcome to Java. Java is one of the most widely used languages in the world, especially in big companies, banks, and Android apps. It has a reputation for being a strict and organized language, but don’t worry, we’ll get used to it together

The first thing we want to learn is how to display something on the screen

public class Main {
    public static void main(String[] args) {
        System.out.println("hey, I like pizza");
    }
}

Run the code. You should see

hey, I like pizza

What is all that boilerplate around our System.out.println? Don’t panic. Right now, we don’t need to fully understand it. Just know that every Java program needs this structure to work. Think of it as the frame of a painting: it’s always there, the actual code goes inside

The line that does the work is

System.out.println("hey, I like pizza");

System.out.println is how Java displays text on the screen. The ln at the end means line, so it prints and then goes to a new line

Three things to notice

• The text goes inside double quotes ""
• Every statement ends with a semicolon ;. Forget it and Java will refuse to run
• The { } braces define blocks of code: they group the lines that belong together

Try removing the ; and run the code. Read the error, that’s how you learn to recognize the compiler’s messages

We can print several lines, one after another

public class Main {
    public static void main(String[] args) {
        System.out.println("Hello");
        System.out.println("World");
        System.out.println("I have 2 dogs");
    }
}

Three lines, three messages. Each one ends with ;

There is also System.out.print without ln. The difference: it does NOT go to a new line after printing

public class Main {
    public static void main(String[] args) {
        System.out.print("Hello");
        System.out.print("World");
    }
}

Output

HelloWorld

Notice that Hello and World are stuck together, because print does not add a new line between them. Most of the time, you’ll want println, but it’s good to know both exist

Mission: First Transmission

The station’s communication array just came online. Send out your very first status report to confirm the link is active.

Write four System.out.println statements inside main that display exactly these four lines:

Cyberstars Station
Antenna: active
Signal: stable
Hello from orbit, cadet!

Match the text exactly, line by line. Don’t forget the quotes and the ; at the end.