Top 10 Java Libraries to Use in 2023

Zoltan Fehervari

April 23, 2023

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Don't let outdated libraries hold you back in 2023. Our handpicked selection of the best Java libraries will take your coding to the next level. Start coding smarter today!


We'll dive into the Top 10 Java libraries for 2023, providing you with a comprehensive overview of these powerful tools and how they can enhance your development projects. So, whether you're a seasoned Java developer or just starting your journey, let's explore the best Java libraries that you should be incorporating into your toolkit!

But first, let’s see what Java libraries are and how to install them...

What is a java library?

Java libraries are collections of pre-written code that developers can utilize to streamline their work and accomplish specific tasks more efficiently. These libraries consist of classes, methods, and interfaces designed to handle common programming challenges, such as reading and writing files, handling network connections, or processing data. By leveraging Java libraries, developers can save time and effort, as they don't have to write these functionalities from scratch.

Java libraries can be standard or third-party. Standard libraries are included in the Java Development Kit (JDK) and are an integral part of the Java programming language. These libraries, such as java.lang, java.util, and, cover a wide range of functionalities and are readily available for developers to use.

On the other hand, third-party libraries are developed and maintained by external organizations or individual developers. They often focus on specific functionalities or use cases, such as data manipulation, logging, or testing. 

Framework vs Library?

A framework serves as a foundation for building and deploying applications rapidly, providing resources that enable faster development and improved user experience. Conversely, a library enhances an application's functionality by offering pre-written code for specific tasks. Developing a custom library allows us to reuse its functions across multiple applications, streamlining the development process.

How to install java libraries?

To install Java libraries, follow these steps:

  • Download and extract the library from its website. Find the library you want to install and download the necessary files, usually in the form of a JAR file or a ZIP archive containing JAR files and documentation.

  • Locate the JAR file(s) for the library and the API documentation. You need to know where these files are located on your computer to add the library to your Integrated Development Environment (IDE) like Eclipse or NetBeans.

If you are using Eclipse:

  1. 1
    Open the "Preferences" window in Eclipse.
  2. 2
    Create a new user library to add the downloaded JAR files. This will make it easy to use the library in multiple projects.
  3. 3
    Add the JAR files to the newly created user library.
  4. 4
    In your project, right-click on the "Java Build Path" and select "Configure Build Path." Then, add the user library you created earlier to your project.

If you are using NetBeans:

  1. 1
    Right-click on the "Libraries" node in your project and select "Add JAR/Folder".
  2. 2
    Browse to the location of the JAR file(s) you downloaded and extracted, then add them to the project.
  3. 3
    If necessary, right-click in the editor window and click "Fix Imports" to resolve any missing import statements.

For use outside of your IDE, add the JAR file(s) to your Java classpath. The process for setting the classpath varies depending on your operating system.

These steps should help you install Java libraries in your preferred development environment.

JUnit (Framework)

Although JUnit is technically a testing framework, it is widely referred to as a library due to its crucial role in Java development. JUnit ensures the quality and reliability of Java applications through comprehensive testing. It provides annotations and assertion classes for writing tests in Java, making it a must-have tool for developers.

JUnit framework example - Bluebird

In this code snippet, we import the JUnit Test class and use it to create a simple test for an addition operation. The test checks whether the sum of 2 and 3 is equal to 5 using the assertEquals method.

Google Guava

Google Guava is an open-source set of libraries that includes essential collections, utilities, concurrency, string manipulation, and more. With a simple and elegant design, Google Guava simplifies the process of creating shared libraries and utility classes, offering a wide range of features, including I/O utilities, string utilities, hashing, and caching.

Google Guava - Bluebird

This code snippet demonstrates a simple example of using Google Guava's Joiner class to join an array of strings into a single string. The Joiner is created with a specified delimiter, in this case, a space character. The join() method then concatenates the elements of the words array using the delimiter, creating a single string sentence. Finally, the sentence is printed to the console, resulting in the output "Guava is awesome".

Apache Commons

Apache Commons is a collection of reusable Java components that provide various utilities for tasks like file I/O, mathematical operations, and data structures. It's an essential library for many Java developers, as it simplifies everyday programming tasks.

Apache Commons - Bluebird

Here, we use Apache Commons Lang's StringUtils to trim whitespace from a string and print the result.

SLF4J (Simple Logging Facade for Java)

SLF4J is an abstraction layer for various logging frameworks, enabling developers to plug in their desired logging framework at deployment time. While technically an API, SLF4J is commonly included in discussions about Java libraries due to its significant role in managing and organizing logging output in Java applications.

SLF4J API Module - Bluebird

This code demonstrates the use of the SLF4J logging facade. We import the necessary classes and create a logger instance for our class. Then, we use the logger to log an informational message.

Jackson Databind

Jackson is an open-source JSON processing library that allows for the conversion of JSON into Plain Old Java Objects (POJOs) and vice versa. Its data binding and annotations make it easy to convert POJO objects into data formats or generate POJOs from data, increasing code reliability and efficiency.

Jackson Databind - Bluebird

In this Jackson Databind example, we use the ObjectMapper class to deserialize a JSON string into a Person object. The readValue method takes the JSON string and the target class as arguments.

Mockito (Framework)

Mockito is a popular mocking framework often mentioned alongside Java libraries. It simplifies the process of creating mock objects for unit testing, allowing developers to avoid spinning up an entire environment during testing.

Mockito - Bluebird

In this Mockito example, we create a mock of the List interface and define the behavior of the get and size methods. The when method specifies the conditions, and thenReturn provides the mock responses.

Kotlin Standard Library

Although Kotlin is a separate programming language, its standard library is designed to be fully interoperable with Java, allowing developers to use Kotlin's expressive syntax and powerful features alongside Java code. The Kotlin Standard Library provides essential higher-order and extension functions for everyday work.

Kotling example - Bluebird

In this Kotlin example, we create an ArrayList of strings using the ArrayList class from Java. We then use Kotlin's map and filter functions from the Kotlin Standard Library to convert the strings to uppercase and filter out strings with a length greater than 5. Additionally, we demonstrate Kotlin's built-in list creation and manipulation functions to create a list of numbers and double them using the map function.


Logback is a newer logging framework than log4j, offering enhancements and improved performance. It is often included in discussions of Java libraries due to its widespread use and importance in handling logging tasks within Java applications.

Logback - Bluebird

In this Logback Classic Module example, we create a LogbackExample class with a main method that logs an info and an error message using Logback. The LoggerFactory.getLogger method is used to get a logger instance for the class.

Apache Maven (Build Tool)

Apache Maven is a build tool that manages project configurations, documentation, and dependencies by specifying them in a pom.xml file. While not technically a library, Maven's essential role in building and deploying Java projects makes it worthy of mention in this list.

Apache Maven - Bluebird

This example demonstrates a simple Maven pom.xml file that defines a Kotlin project with a dependency on the Kotlin Standard Library 1.6.0. It also includes the kotlin-maven-plugin to compile the Kotlin code.

Spring Framework

The Spring Framework is an open-source framework that simplifies the development of Java applications. It provides a comprehensive infrastructure for building, deploying, and maintaining Java applications, making it easier for developers to focus on their application logic. Although it's a framework, its importance in the Java ecosystem makes it a valuable addition to this list.

Spring library - Bluebird

In this example, we use Spring Framework's AnnotationConfigApplicationContext to load an AppConfig class, which configures our application. We then get a bean of type MyService and call its doSomething method.

These top 10 Java libraries and frameworks are essential tools for Java developers in 2023. They offer valuable features and functionalities that help streamline development processes and ensure code quality. By incorporating these libraries and frameworks into your projects, you'll be better equipped to create efficient, reliable, and maintainable Java applications.

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