HashMap: Java Collections Framework Video Tutorial, Part 3

A tutorial on HashMap. Maps are data collections that function like lookup tables; basically you can store objects via "keys" (names, IDs, or even complex objects) and quickly retrieve them without having to look through an entire list.

After starting the video, click the maximise button to make it fullscreen so you can see the code!



Code For This Tutorial



App.java:

 
import java.util.HashMap;
import java.util.Map;

public class App {


    public static void main(String[] args) {

        HashMap<Integer, String> map = new HashMap<Integer, String>();
        
        map.put(5, "Five");
        map.put(8, "Eight");
        map.put(6, "Six");
        map.put(4, "Four");
        map.put(2, "Two");
        
        String text = map.get(6);
        
        System.out.println(text);
        
        for(Map.Entry<Integer, String> entry: map.entrySet()) {
            int key = entry.getKey();
            String value = entry.getValue();
            
            System.out.println(key + ": " + value);
        }
        
    }

}

 
Six
2: Two
4: Four
5: Five
6: Six
8: Eight