Java enum example -- they are class instances and can have fields/state and behavior/methods

Coffee.java

public enum Coffee {
    ESPRESSO(2.50, 2),
    LATTE(4.50, 8),
    CAPPUCCINO(4.00, 8),
    AMERICANO(3.00, 8);

    // the 'final' isn't necessary functionally, since you can't change these from outside the class/enum
    // but this does document our intent, and would prevent accidentally adding something inside this enum
    // that modified the field.
    private final double price;
    private final int ounces;

    private Coffee(double price, int ounces) {
        this.price = price;
        this.ounces = ounces;
    }

    public double getPrice() { return this.price; }
    public int getSize() { return this.ounces; }

    public double pricePerOunce() {
        return this.price / this.ounces;
    }
}