Java By Comparison

Favor Java API Over DIY

class Inventory {

    private List<Supply> supplies = new ArrayList<>();

    int getQuantity(Supply supply) {
        if (supply == null) {
            throw new NullPointerException("supply must not be null");
        }

        int quantity = 0;
        for (Supply supplyInStock : supplies) {
            if (supply.equals(supplyInStock)) {
                quantity++;
            }
        }

        return quantity;

    }
}

In the early days of programming, you had to do everything by yourself. In C, for instance, you still need to create a String using a char[] or implement your own list. You had to do this for all kinds of data structures and algorithms. Although this is a nice exercise, it’s also time-consuming and error-prone.

Times have changed. The Java API is ...