The 8 Most Popular Java Experts

Below are eight Java luminaries who have changed the way Java programming is done by writing frameworks, products, tools, or books for the Java community:

1. **James Duncan Davidson**, the founder of Tomcat and Ant. While working as a software engineer at Sun Microsystems (1997–2001), he created Tomcat, a Java-based web server that is still widely used in many Java web projects today. In addition, he developed Ant, a build tool that uses XML to describe the build process and dependency management, which became the de facto standard for building Java-based web applications.

2. **Kent Beck**, the founder of Test-Driven Development and JUnit. He pioneered extreme programming and the test-driven software development methodology. Furthermore, he co-authored JUnit with Erich Gamma, a simple testing framework that became the de facto standard for testing Java-based web applications. The combination of JUnit and test-driven development has changed traditional Java programming methods, although many Java developers were initially resistant to it.

3. **Joshua Bloch**. He led the design and implementation of numerous Java platform features, including language improvements in JDK 5.0 and the highly acclaimed Java Collections Framework. In June 2004, he left Sun Microsystems to become Google's Chief Java Architect. Later, he won the prestigious Jolt Award for his book *Effective Java*, which remains a controversial but essential read for Java developers.

4. **Marc Fleury**, the founder of JBoss. He founded the open-source Java application server JBoss in 2001, which became a controversial yet widely adopted de facto standard for Java-based web applications. Later, he sold JBoss to Red Hat and joined the company to continue its development. On February 9, 2007, he decided to leave Red Hat to pursue personal interests such as teaching, studying biology, music, and spending time with his family.

5. **Craig McClanahan**, the creator of Struts. He developed Struts, a popular MVC framework that most Java developers know how to code in. Due to its early success, almost every early Java web application was implemented using Struts.

6. **Rod Johnson**, the founder of Spring. He is the creator of the open-source Java application framework Spring and served as the CEO of SpringSource. Additionally, Rod's book *Expert One-on-One J2EE Design and Development* (2002) is one of the most influential books on J2EE.

7. **Gavin King**, the founder of Hibernate. He created Hibernate, a popular object/relational persistence solution for Java, and also authored the Java EE 5 application framework Seam. Moreover, he made significant contributions to the design of EJB 3.0 and JPA.

8. **James Gosling**, the father of the Java language. He invented Java in 1994, completing its original design, compiler, and virtual machine. Due to his contributions, he was elected to the National Academy of Engineering. On April 2, 2010, he left Sun Microsystems, which had recently been acquired by Oracle. Regarding his departure, Gosling wrote in his blog: "More precisely, leaving was more meaningful than staying."

P.S. The ranking is purely based on personal preference.