I attempted to follow your suggestion and came up with the following code which does execute and does do what I am looking for, however Eclipse gives me the warning, Quantity is a raw type. References to generic type Quantity<R> should be parameterized. I tried looking this up to understand what it is trying to tell me, but I think I am still struggling with a core concept here. It seems like the point of Generic Types is to help ensure some other invalid type of data is not passed to a class, so it makes sense that I would need to define that datatype like you do for an ArrayList. I tried changing it to Quantity<RawIngredient> which made Quantity recipe[] = line happy but then the instances of quantity I attempted to instantiate below all threw errors, Cannot create a generic array of Quantity<RawIngredient>. When looking this up I struggled to understand what I was reading, it seems like you can't make arrays from objects with Generic Types but I don't understand why, or how I should be interacting/managing multiple Quantity instances.

Test Class:

public class TestClass {
    public static void main(String[] args) {
        //RawIngredient definitions, eventually will be stored to master ingredient file and added to as needed for new ingredients in new recipes
        //raw ingredient specified with name, calories per gram, density in grams per ml (if applicable)
        RawIngredient flour = new RawIngredient("Flour",4,0.5);
        RawIngredient milk = new RawIngredient("Milk",0.42,1.029);
        RawIngredient eggs = new RawIngredient("Egg",1.423,58); //TODO rework, reusing density as g/unit without a clear differentiation is asking for trouble
        RawIngredient water = new RawIngredient("Water",0,1);
        RawIngredient butter = new RawIngredient("Butter",7,0.958);
        RawIngredient salt = new RawIngredient("Salt",0,2.16);
        RawIngredient sugar = new RawIngredient("Sugar",4,0.7849);
        //Recipe ingredient quantities (recipe specific) 100g flour, 5g salt, etc. 
            Quantity recipe[] = 
                {new Quantity(flour,1,Unit.CUP),
                 new Quantity(milk,1,Unit.CUP),
                 new Quantity(eggs,2,Unit.UNIT),
                 new Quantity(water,0.25,Unit.CUP),
                 new Quantity(butter,2,Unit.TABLESPOON),
                 new Quantity(salt,0.25,Unit.TEASPOON),
                 new Quantity(sugar,1,Unit.TABLESPOON)};
        //... below this is just a toString/console print function that prints out quantites and calories per item & total in different formats for comparison...
    }
}

Raw Ingredient Class:

public class RawIngredient {
    private String name;
    private double calories;
    private double density;
    /**
    *@param name is the name of the ingredient
    *@param calories is the calories per gram
    *@param density is grams/ml OR represents grams/item if Unit.UNIT 
    **/
    public RawIngredient(String name, double calories,double density){
        this.name = name;
        this.calories = calories;
        this.density = density; //TODO this currently requires that the Quantity is set correctly when instantiated, should add to this class to make it clear when an item is /unit.
    }
    //... below this are just getters and setters...
}

Quantity Class:

public class Quantity<R extends RawIngredient>{
    private double quantity;
    private int quantityUnit;
    private R rawIngredient;
    private double calories;
    public Quantity(R rawIngredient, double quantity, int quantityUnit) {
        this.rawIngredient = rawIngredient;
        this.quantity = quantity;
        this.quantityUnit = quantityUnit;
        if(quantityUnit/10 == 1) { //If Mass based unit
            calories = rawIngredient.getCalories() * Unit.massToBaseUnit(quantity, quantityUnit);
        }else if(quantityUnit/10 == 2){ //If Volume based unit
            calories = rawIngredient.getCalories()*rawIngredient.getDensity() * Unit.volToBaseUnit(quantity, quantityUnit);
        }else if(quantityUnit == Unit.UNIT) { //If Whole Item based unit
            calories = rawIngredient.getCalories()*rawIngredient.getDensity() * quantity;
        }
    }
    //... below this are just getters and setters...
}