Builder Pattern in Java

new PizzaOrder("LARGE", true, false, null, "Ring the bell");
new PizzaOrder("SMALL", false, true, List.of("Corn"), null);

import java.util.ArrayList;
import java.util.List;
 
public class Pizzas {
    static final class PizzaOrder {
        private final String size;
        private final boolean extraCheese;
        private final List<String> toppings;
        private final String note;
 
        private PizzaOrder(Builder b) {
            this.size = b.size;
            this.extraCheese = b.extraCheese;
            this.toppings = List.copyOf(b.toppings);
            this.note = b.note;
        }
 
        static Builder builder(String size) { return new Builder(size); }
 
        @Override
        public String toString() {
            return size + (extraCheese ? " + cheese" : "") + " " + toppings
                + (note == null ? "" : " [" + note + "]");
        }
 
        static final class Builder {
            private final String size;
            private boolean extraCheese;
            private final List<String> toppings = new ArrayList<>();
            private String note;
 
            private Builder(String size) { this.size = size; }
 
            Builder extraCheese() { extraCheese = true; return this; }
            Builder topping(String t) { toppings.add(t); return this; }
            Builder note(String n) { note = n; return this; }
 
            PizzaOrder build() {
                if (toppings.size() > 5) {
                    throw new IllegalStateException("At most 5 toppings");
                }
                return new PizzaOrder(this);
            }
        }
    }
 
    public static void main(String[] args) {
        PizzaOrder navika = PizzaOrder.builder("LARGE")
            .extraCheese()
            .topping("Paneer").topping("Capsicum")
            .note("Ring the bell")
            .build();
        PizzaOrder advitha =
            PizzaOrder.builder("SMALL").topping("Corn").build();
        System.out.println(navika);
        System.out.println(advitha);
    }
}