Java Playground

A starter program to experiment with. Edit it here, press Copy, paste it into a file called Main.java, and run java Main.java in a terminal (Java 25 or newer). Lesson 2 shows how to install Java.

import java.util.List;

record Item(String name, double price, int quantity) {
    double total() { return price * quantity; }
}

public class Main {
    public static void main(String[] args) {
        List<Item> basket = List.of(
            new Item("Notebook", 3.50, 4),
            new Item("Pen", 1.20, 10),
            new Item("Backpack", 39.90, 1)
        );

        for (Item item : basket) {
            System.out.println("%-10s %3d x %6.2f = %7.2f".formatted(item.name(), item.quantity(), item.price(), item.total()));
        }

        double total = basket.stream().mapToDouble(Item::total).sum();
        System.out.println("Total: %.2f".formatted(total));
    }
}

Edit the code, copy it into Main.java and run java Main.java (Java 25+). How to set up Java

Output

Notebook     4 x   3.50 =   14.00
Pen         10 x   1.20 =   12.00
Backpack     1 x  39.90 =   39.90
Total: 65.90

Ideas to try

Apply a 10% discount when the total is over 50 (lesson 13).
Sort the basket by item total, highest first (lesson 43).
Group items into "cheap" and "expensive" with partitioningBy (lesson 47).
Read the items from a CSV file instead (lesson 51).
Reject items with a negative price in a compact constructor (lesson 32).

Running Java without installing it

If you can't install a JDK, search for an online Java compiler that supports Java 25 or later, paste the code, and run it there. On older Java versions, the traditional public class Main form used here works everywhere from Java 16 (records) onwards.

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