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Java Arrays

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Adding and Removing Items Means Copying

6:52 with Travis Alstrand

An array's length is immutable, meaning it cannot be changed. If you want to add or remove, you need to declare a new array and copy into it. Don't worry you won't be doing this too much.

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Example ArrayList code

// This is coming from the Java Collection Framework
import java.util.List;
import java.util.ArrayList;

// This is using Generic syntax, we'll get to it...
List<String> friends = new ArrayList<>(); 
friends.add("Brian"); // adds "Brian" to the friends list
friends.size(); // returns 1
friends.contains("Brian"); // returns true
friends.remove("Brian");
friends.size() // returns 0

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    power of arrays, it's time to look at some of their limitations. 0:00
    Have we been dealing with arrays where we either know all of the items 0:00
    at declaration time, or at least know how many will be there eventually. 0:04
    In reality, that's not always the case, is it? 0:08
    I'm sure you can imagine programs where we're taking input from a user, 0:11
    and they want to either add or remove elements from the array. 0:16
    If you recall, when we first started talking about this 0:19
    fancy new data structure, we talked about how its length is immutable. 0:22
    Now remember, that means it can't be changed. 0:26
    The reason for this immutability was because the declaration 0:29

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