Java HashMap Tutorial with Example
The Java HashMap data structure is one of the most popular and flexible in the language. Key-value pairs may be stored in a HashMap, and their values can be quickly retrieved using the corresponding keys. This lesson will walk you through the fundamentals of HashMap Java, whether you’re new to Java or an experienced programmer seeking to brush up on your knowledge. In addition, a Java Online Course might provide you with useful Java lessons if you’re looking for a thorough learning experience.
What is a HashMap in Java?
The Java Collections Framework, of which HashMap is a component, is a collection of classes and interfaces that together enable efficient and versatile data structures. To store key-value pairs in an unsorted fashion, one may make use of a HashMap, which is an implementation of the Map interface. This implies that you may rapidly obtain a value by using its corresponding key since each key corresponds to a single value.
How to Use HashMap in Java
Let’s look into some instances of real-world HashMap use in Java.
Creating a HashMap
You must bring in the Java.util.HashMap class if you want to create a HashMap. To make your own, follow these steps:
To demonstrate, we’ve built an ageMap HashMap that stores integer values and string keys. You are free to use your custom typefaces in lieu of these.
Adding Key-Value Pairs
You may use the put method to add new key-value pairs to your HashMap:
If you know the value’s key, you can use it to get the value:
Iterating Through HashMap
Using a loop, you may traverse over the HashMap’s keys and values. The for-each loop is seen below.
The ages of everyone in the age map will be printed out.
Removing Key-Value Pairs
The delete method is used to get rid of a key-value pair.
The age of “Bob” has been removed from the age map at this time.
HashMap Java Online Course
Consider taking a Java online course if you want to learn more about HashMap and other Java subjects. To help you reach your goal of becoming a good Java programmer, these courses offer you a structured curriculum, hands-on exercises, and coaching from industry professionals.
An online Java course may be modified to meet the needs of students with varying levels of programming expertise. You won’t only learn about HashMap but also many other important Java concepts, best practices, and advanced approaches.
HashMap Operations and Methods
After learning the fundamentals of HashMap in Java, we can go on to explore some of the most typical operations and methods for working with HashMap. To fully make use of this flexible data format, a firm grasp of these processes is required. These operations enable you to make effective use of HashMap for a wide range of purposes, from adding and deleting key-value pairs to iterating over items and searching for particular values. The HashMap class in Java has several more methods for more complex data manipulation and retrieval in addition to these basics.
When it comes to storing key-value pairs, Java’s HashMap is one of the most effective and flexible options available. It’s a great option for a wide variety of programming jobs because of its simplicity and ease of usage. You may learn more about HashMap and how you can best use it in Java programs by playing around with it and practicing what you’ve learned. If you want to become a Java expert, taking an online Java course may help you learn the language quickly and improve your abilities. Happy programming!