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

How to sort a **HashMap** by key and value is one of the most important interview questions employers ask, and there is no single answer to it. This topic requires some knowledge of **TreeMap**, which we will discuss in this lesson.

Let's discuss some of the ways to sort a **HashMap**.

## Using a TreeMap
Elements are stored in a **TreeMap** in sorted order by default, we can create a **TreeMap** and then add all the elements from our **HashMap** to the **TreeMap** using the `putAll()` method. 

How to sort a **HashMap** by key and value is one of the most important interview questions employers ask, and there is no single answer to it. This topic requires some knowledge of **TreeMap**, which we will discuss in this lesson.

Let's discuss some of the ways to sort a **HashMap**.

# Using a TreeMap
Elements are stored in a **TreeMap** in sorted order by default, we can create a **TreeMap** and then add all the elements from our **HashMap** to the **TreeMap** using the `putAll()` method. 

Let's learn how to sort a HashMap by key and value.

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

TreeMap: HashMap Sorting

Using a TreeMap