Variables (Strings)

We saw how to store numbers. But what about text? In Java, the type for text is called String (with a capital S, this matters)

public class Main {
    public static void main(String[] args) {
        String name = "Tommy Vercetti";
        System.out.println(name);
    }
}

Run it. You’ll see Tommy Vercetti

We can change the value just like with numbers

public class Main {
    public static void main(String[] args) {
        String name = "Tommy Vercetti";
        System.out.println(name);

        name = "Lance Vance";
        System.out.println(name);

        name = "Paul";
        System.out.println(name);
        System.out.println(name);
        System.out.println(name);
    }
}

Output

Tommy Vercetti
Lance Vance
Paul
Paul
Paul

Notice that the second time we change name, we don’t write String again. We only write the type once, when we first declare the variable. After that, Java already knows the type

Don’t forget the quotes. The code below will not work

public class Main {
    public static void main(String[] args) {
        String name = Paul;   // error
    }
}

Java thinks Paul is a variable, doesn’t find one with that name, and gives an error. To say "this is text, treat it exactly as written", we put it in ""

A subtle example

public class Main {
    public static void main(String[] args) {
        String Kent = "Booooo";
        String name = Kent;
        System.out.println(name);
    }
}

This prints Booooo, not Kent. Why? Because Kent without quotes is treated as a variable, and that variable holds "Booooo". To actually print the word Kent we’d write

public class Main {
    public static void main(String[] args) {
        String name = "Kent";
        System.out.println(name);
    }
}

A nice extra in Java: text variables behave a bit like objects. We can already peek at one useful trick

public class Main {
    public static void main(String[] args) {
        String name = "Tommy Vercetti";
        System.out.println(name.length());
    }
}

Output 14. .length() tells us how many characters the text has. Spaces count too. We’ll explore many more of these methods in a later lesson, for now just notice the dot syntax

Mission: Crew Roster Fix

The station’s crew roster has a bug: the names were entered without quotes, so Java thinks they are variables instead of text.

Fix the three variable assignments, hero1, hero2 and hero3, so the program compiles and prints the crew names correctly.

Example

Your program should print

Lance Vance
Diaz
Mercedes