Gain insights into Java Collections Framework. Delve into lists, sets, and hashmaps. Learn about data modification, sorting, thread-safety, and internal workings for efficient usage.

Collection is one of the most important topics for Java programming. Without the proper knowledge of every collection type in Java, it becomes difficult for you to decide which option to pick in a particular scenario.

This course will give you a great understanding of all collection types available in the Collections Framework like lists, linked lists, sets, and hashmaps. 

After completing this course, you will know how data can be modified within a collection, how to sort a collection, and how it can be made thread-safe. You will also cover the internal working of each Java collection so you can work with them more efficiently.

Collections in Java

Iterating a **HashMap** is a bit challenging compared to a **List** or a **Set** as it contains pairs of elements. In a map, each key-value pair is called **Entry**. The `entrySet()` method returns the **Set** view of the mapped elements. We can iterate over this Set using any of the below approaches.

# Iterating using a `for` loop
We can easily iterate the **EntrySet** returned by the `entrySet()` method using an enhanced for loop. The **Entry** class contains two methods: `getKey()` and `getValue()`, which can be used to get the key and value respectively.

Let's see how we can iterate the elements of a HashMap.

Let's Begin

Lists in Java

LinkedList in Java

CopyOnWriteArrayList in Java

Sets in Java

TreeSet in Java

HashMap In Java

TreeMap in Java

LinkedHashMap in Java

Additional Map Implementations

Arrays Class

Collections Class

HashMap: Iteration