10 Best Testing Tools and Libraries for Java Developer

Java Developer Testing Tools and Libraries 2021/2022. Mr. Programmer, this post is for you; It contains the 10 best Testing Tools and Libraries for Java Developer. If this is your first time on this website, please note that I’ve written several articles in the last few weeks about what Java developers should know in 2021. They includes, programming languages, libraries, and frameworks. But if you only have one thing to change or master, it should be your testing skills. One of the disciplines that distinguishes skilled developers from amateurs is testing.

Before you continue, browse through the Best Windows Pen-testing Ethical Hacking Tools 2021. Also, you can update your library with the 9 Best WiFi Penetration Testing Tools Hackers Use in 2021. After reading those articles, then you can proceed to the 10 Essential Unit and Integration Testing tools for Java Programmers.

It’s not about following test-driven development (TDD), business-driven development (BDD), or any other testing methodologies; at the very least, you must write code to automatically test your code. Many Java developers use continuous integration to write unit and integration tests that run automatically during build time.

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Many Java developers use continuous integration tools like Jenkins or TeamCity to write unit and integration tests that run automatically during build time.

If you’re wondering why a programmer should concentrate on automation testing, let me tell you that the value of automation testing is constantly increasing as more people become aware of it and DevOps emerges.

Generally, a lot of companies favor programmers who can write unit tests. They also prefer those who can easily demonstrate a thorough understanding of various unit testing systems, libraries. They usually choose programmers who can use resources such as JUnit, Selenium, REST-Assured, as well as the Spock system, among others.

As a Java developer, we work on a wide range of projects, from writing core Java code to developing JSP pages, REST APIs, and even Groovy scripts for construct automation. As a result, we must also be aware of the various resources available to us in order to automate our processes.

Let me give you this example. I previously had only learned JUnit recently, so when it came time to test my JSP pages, I was completely lost until I discovered Selenium. REST Assured is similar in that I normally test my REST API with the curl command. But REST Assured brings REST API unit testing to a new stage of learning.

10 Essential Unit and Integration Testing tools for Java Programmers

Since I believe that a programmer is only as good as their software, I spend my free time learning and exploring new tools and libraries, and this list is part of that research.

In this article, I’ll discuss ten of the best and most important tools, frameworks, and libraries for Java developers who need to write unit and integration tests for their various Java projects.

1. JUnit

JUnit, in my opinion, does not need any introduction. Even if you’re a novice Java programmer, you’ve probably heard of it. It enables you to write Java code unit tests.

JUnit integration is available in almost all major IDEs, including Eclipse, NetBeans, and IntelliJIDEA, allowing you to write and run unit tests directly from the IDE.

The majority of us are still using JUnit 4, but JUnit 5 has already been published and is likely to be the next big thing this year. JUnit supports Java 8 functionality and can be used for both unit and integration testing.

If you’re completely new to unit testing, particularly Java unit testing, this Udemy course Learn Java Unit Testing with Junit & Mockito in 30 Steps is a good place to start. On Udemy’s sale, you can get it for just $10.


2. Mockito

There are several mocking frameworks for Java classes, such as PowerMock and JMock, but I prefer Mockito because of its simple API, extensive documentation, and numerous examples.

Mocking is an important part of modern-day unit testing because it allows you to test your code without any dependencies, which is why I recommend that every Java developer learn a mocking framework in addition to JUnit.

Mockito is my preferred mocking framework, but you can also try PowerMock or JMock.

If you plan to stick with Mockito and learn the framework, this JUnit and Mockito Crash Course on Udemy is a great place to start.


3. REST Assured

REST service testing and validation in Java is more difficult than in dynamic languages like Groovy. Additionally, REST Assured extends the ease of use of these languages to the Java world. It’s an excellent method for integrating REST APIs.

However, if you know that you’re very serious about writing integration tests for your REST API, the REST Assured and REST API Testing Automation: via REST Assured & HTTP Client course on Udemy is a good place to start. I’ve already signed up for this course and plan to learn this method in 2021.

REST Assured
REST Assured

Lastly, it includes many types of REST API testing, such as Rest Assured Java Automated REST API Testing and POSTMAN and HTTP Client RESTful Web Service Testing.

4. Selenium

Selenium is the most widely used method for Java UI testing, since it helps you to test your JSP pages without having to open them in a browser.

JUnit and Selenium can be used to analyze the user interface of your web application. You can also write web application acceptance tests with it.

I’m also studying Selenium WebDriver with Java – Basics to Advanced on Udemy because I’m new to it.

So, if you want to learn how to use Selenium to unit test your code, you can use its method, which is probably the best place to start.

You’ll learn everything there is to know about Selenium Webdriver, as well as strong Core Java fundamentals. This is especially useful for testers who want to learn Java for automation testing in addition to Selenium.

5. TestNG

The TestNG is a testing system based on JUnit and NUnit. But it comes with many new features that make it more efficient and easy to use. Its framework includes annotations as well as the ability to run your tests in arbitrarily large thread pools. You can do this with a variety of policies (all methods in their own thread, one thread per test class, etc).

Because of the use of annotations from JUnit 4 and the integration of the Hamcrest matchers, the distance between JUnit and TestNG has narrowed, but the choice is yours.

TestNG Complete Bootcamp For Beginners – Novice To Ninja is a good place to start if you want to learn TestNG for unit testing your Java code.

The guide gives you a step-by-step guide to learning the TestNG Framework (Next Generation) so you can achieve your automation goals faster.

TestNG - Java Developer Testing Tools

6. Spock Framework

Spock is another Java and Groovy program testing and specification platform. Since it’s written in Groovy, it’s a very expressive and concise specification language.

Furthermore, Spock improves the readability and maintainability of your tests. In addition, it is compatible with most IDEs, build software, as well as continuous integration servers thanks to its JUnit runner.

Unfortunately, I was unable to locate a useful course for learning the Spock framework; however, the Java Testing with Spock book is a good place to begin.

Spock Framework - Java Developer Testing Tools
Spock Framework

7. Cucumber

Cucumber is another great tool for automated integration tests. But its specification capability sets it apart from those in the group.

Surely, Cucumber combines specification and test documents into a single living document. Since Cucumber tests them automatically, the specifications are still up to date.

Selenium WebDriver with Java & Cucumber BDD is a good course to learn and incorporate Cucumber in your project if you want to create a complete web automation testing system and simulate user behavior on a web application.

Cucumber Tool - Java Developer Testing Tools
Cucumber Tool

8. Spring Test

Spring MVC has a powerful test system that helps you to run comprehensive tests without having to open a web container.

It’s one of the most useful libraries for writing Spring applications’ automated tests. Spring-powered systems, including MVC controllers, benefit from first-class support for writing unit and integration tests.

Spring Test DbUnit combines the Spring Test framework with DbUnit, and Spring Test MVC HtmlUnit combines the Spring Test MVC framework with HtmlUnit.

These tools make it simple to automate the testing of your Spring MVC application.

9. DBUnit

DBUnit is among the best Java Developer Testing Tools. A database is an essential component of many Java programs, including Core Java and Web applications, and it is likely the most difficult thing to unit test.

Connecting to a Dev or UAT database for integration testing is unreliable since someone can modify the data and schema, such as tables and stored procedures, causing the automatic integration test to fail.

DbUnit is a JUnit extension that can be used to initialise the database into a known state to insure that the database contains the correct data before any integration test.

DbUnit has its own flaws, but it is a very valuable method because it allows one to isolate the processing of test data from the code that is being evaluated.

10. Robot Framework

The Robot Platform is a generic test automation framework based on Python for acceptance testing and test-driven development.

It’s a tabular test data syntax keyword-driven testing system. It can be used to verify distributed, heterogeneous systems that involve interaction with several technologies and interfaces.

If you want to learn more about this fantastic platform for integration tests, Udemy’s Robot Framework Test Automation course is a perfect place to start. It’s a two-part course that explores the Robot framework’s simple and advanced functionality.

Robot Framework - Java Developer Testing Tools
Robot Framework

11. Postman

This is yet another useful testing tool for Java developers, particularly full-stack Java developers who work on both the frontend and backend. Postman helps you to make direct API calls and interpret the results.

For example, you should inspect response headers and error codes in addition to checking whether your API calls are functioning or not. Similarly, you can set headers and query parameters when submitting requests, making dealing with APIs even simpler.

Postman also helps you to save and replay your API call, allowing for further in-depth checking. In 2021, if you are a full-stack Java developer, I strongly advise you to learn this valuable method. If you need a lesson, I highly recommend Valentine Despa’s Postman: The Complete Guide – REST API Testing course on Udemy. This 13.5-hour course is ideal for learning how to use Postman to test REST APIs.

Postman - Java Developer Testing Tools


We have come to the conclusion section of the top 10 Testing Tools and Libraries for Java Developer. It means that this concludes a discussion of some of the most important unit and integration testing tools, frameworks, and libraries for Java developers. There are several other libraries, such as AssertJ and Hamcrest, that can assist you in writing beautiful and fluent tests if you take it slowly.

Learn a programme or library that you can use in your day-to-day work as a starting point. For example, if you work with Java UI, you can learn Selenium first so you will be able to rely more on this tool.

In summary, if you deal with REST APIs, you can learn REST Assured. Similarly, if you’re doing a lot of core Java growth, JUnit 5 should be your first port of call.

Finally, it doesn’t matter which method you begin with first; just make sure you spend some time in the New Year improving your skills.

Other Programming Resources and Articles You may like: Java Developer Testing Tools

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P. S. – If you’re new to Java and want to learn the basics before diving into these software and libraries, take a look at this list of Top 10 Java Courses on Medium, Coursera, Pluralsignt and Udemy. It includes a variety of Java courses that will help you become an expert Java programmer. Java Developer Testing Tools.

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