Intermediate 17 min

Collections Framework

ArrayList, HashMap, and when to pick each.

What you will learn

Use ArrayList add/get
Store key-value in HashMap
Iterate with for-each

java

import java.util.*;

List<String> tags = new ArrayList<>();
tags.add("java");
tags.add("api");

Map<String, Integer> stock = new HashMap<>();
stock.put("widget", 42);

for (String t : tags) {
    System.out.println(t);
}

Try it yourself

Count word frequency in a sentence using a HashMap.