print vs println 🖨️

Java has two ways to say things:

• System.out.println(...) says it, then moves to a new line (like pressing Enter).
• System.out.print(...) says it and stays on the same line.

public class Main {
    public static void main(String[] args) {
        System.out.print("Zoom");
        System.out.print("Zoom");
        System.out.println("!");
        System.out.println("Done");
    }
}

That prints:

ZoomZoom!
Done

Notice there's no space between Zoom and Zoom. Java prints exactly what you give it, nothing more.

Joining text with +

The + sign glues text together:

public class Main {
    public static void main(String[] args) {
        System.out.println("Mars" + "Rover");
        System.out.println("Mars " + "Rover");
    }
}

The first line prints MarsRover, the second prints Mars Rover, because the second one has a space inside the quotes.

Text + numbers

You can glue numbers onto text too:

public class Main {
    public static void main(String[] args) {
        System.out.println("Moons of Mars: " + 2);
    }
}

🌍 Fun fact

The Curiosity rover has been exploring Mars since 2012. Every command it gets is checked very carefully, because one missing space or semicolon could mean a very expensive mistake!