Maps

In this section, we're going to take a look at Java's Map data structure. I wanted to start with a bunch of already formatted information, so I have created a little program on my own. You will find the following program in the companion files for the book. Take a look through it and make sure you understand how it works:

package maps; 
import java.util.*; 
public class Maps { 
    public static void main(String[] args) { 
        String[] allNames =   
            //<editor-fold desc="raw names data"> 
            {"Jane", "Addams", 
            "Muhammad", "Ali", 
            "Stephen", "Ambrose", 
            "Louis", "Armstrong", 
            "Joan", "Baez", 
            "Josephine", "Baker", 
            "Eleanor", "Roosevelt", 
            "Frank", "Sinatra" 
            }; 
            //</editor-fold> 
        String[] firstNames = new String[allNames.length/2]; 
        String[] lastNames = new String[allNames.length/2]; 
        for(int i = 0; i < allNames.length...