Click here to navigate the course.

Drag the edges to resize the window.

In Projects, you can keep track of your progress as you go throught the tasks. Check each item as you complete it!

Code Editor

Great! Another useful built-in data structure in Java is the HashMap.

Although the name of the data structure might not make sense to you immediately, think of it as a real-life dictionary. A dictionary contains a set of words and a definition for each word. A HashMap contains a set of keys and a value for each key.

If we look up a word in a dictionary, we can get the definition. If you provide a HashMap with a key that exists, you can retrieve the value associated with the key.

Declaring a HashMap is shown in the following example:

HashMap<String, Integer> myFriends = new HashMap<String, Integer>();

In the example above, we create a HashMap object called myFriends. The myFriends HashMap will store keys of String data types and values of type Integer.

Note: the String object allows you to store multiple characters, such as a word in quotations (e.g. "Rats!").

report a_bug
If you see a bug or any other issue with this page, please report it here.