“Write once, run everywhere.” This cross-platform capability thanks to the Java Virtual Machine (JVM) is what makes Java consistently one of the most in-demand languages until now. Despite being over 20 years old, it still powers many of the technologies we use today. Most major corporations actually hire Java developers to build their products; in fact, 90% of Fortune 500 companies use Java for back end development.

If you’re one of the thousands of employers seeking Java developers, it’s crucial to know the skills and characteristics that separate great Java developers from the rest.

Strong skills in Object-Oriented Programming

Since Java is basically an object-oriented language, great Java developers have a solid knowledge and understanding of the concepts of object-oriented programming (OOP). These developers are able to implement object-oriented design patterns. They are also well-versed in OOP basics like abstraction, inheritance, composition, class, object, interface, encapsulation, etc.

It takes both skill and a broad experience for Java developers to be able to structure their code efficiently in an object-oriented manner.

A sound understanding of garbage collection

Java is a programming language with garbage collection. This means that it automatically frees up the occupied memory of unused objects or those that are no longer referenced by a reachable Java object. Languages without garbage collection such as C and C++ require programmers to implement manual memory management in their code.

Some programmers favour manual memory management over garbage collection mainly because of the control it gives to programmers. At times, a poorly implemented garbage collection can be harmful to the code, but Java offers many options for tuning the garbage collector to improve its efficiency.

Hiring Java developers who know how to optimise garbage collection will be a great asset to your development team, as well as those who are experienced in class loading and in using debuggers.

More noteworthy hard skills

Here are some more important skills to take note of, as enumerated by Gaurav Sharma, Sharabh Technologies Business Development Manager (IT):

Database skills are important for Java developers. A great developer knows…  

• SQL Queries (e.g. Inner and Outer Joins, Group By, Having, With, etc.)
• Stored procedure (a set of SQL statements that can be saved so it can be reused and shared by multiple programs)
• Triggers
• Cursors
  

If the job is related to networking or distributed applications, the Java developer should have…

• Knowledge of protocols such as IP (Internet Protocol, a connectionless protocol), HTTP (Hypertext Transfer Protocol, often called “The protocol of the Internet”), FTP (File Transfer Protocol), and TCP and UDP (Transmission Control Protocol and User Datagram Protocol, which are both used to transmit network data to and from server and client applications).
• Skills in working on sockets (endpoints in communication between two computers or programs across a computer network), RMI or Remote Method Invocation (an API that allows programmers to create distributed applications in Java), and RCP or Rich Client Platform (a software development platform that helps software developers build new applications rapidly).   

If the job is related to Java-based web apps, the Java developer should be skilled in:

• JSP (Java Server Page) and servlets
• Web Frameworks (e.g. Struts, Spring)
• Web service architecture strategies (SOAP - Simple Object Access Protocol or REST - REpresentational State Transfer)
• Web technologies (e.g. HTML, CSS, Javascript, and JQuery)
• Markup languages (e.g. XML, JSON)

If the project is on Java UI, then the developer should know:

• Applets (a small program written in Java which is also able to run in HTML)
• Frameworks such as Swing, AWT, JavaFX

Related article: 8 Mistakes to Avoid When Hiring a Programmer

Passion for coding

While not a skill but a trait, this is one thing you should definitely search for when you hire Java developers. Most developers, if not all, who have a passion for coding often have projects outside work. These projects can be open-source projects or even personal projects. These projects are also not strictly Java-based projects—it’s the experience that counts.

As they try out different projects fueled by their passion for coding, they are able to build a wider skill set and a broader experience than those who code only on work projects.

Great communication skills

Applicable to all tech talents regardless of the language, it’s advantageous to hire Java developers with great communication skills. Despite the long hours of coding in front of their computers, often with their headphones on, programming is still a discipline that is essentially social.

Communication is critical in building a great product. There’s a lot of collaboration happening among teams throughout the development. With this, a great Java developer is excellent in both oral and written communication, and he/she is also able to share his/her ideas to his colleagues effectively, whether they have a technical background or not.   

Client Handling Skills

Besides great skills in programming, you should also hire Java developers who have great client handling skills. This can be hard to see during the interviews, but you should observe how an applicant handles questions and queries during this stage. How did he/she accept your questions? Was he able to answer all the questions? Were there questions he couldn’t answer? How did he respond?

Client handling skills will come in handy, especially since your Java developer will have to deal with different kinds of clients, developers, and managers like you as you move forward. When an applicant is able to answer your questions with ease and confidence, then that can be an indicator that he/she possesses client handling skills to some extent.

Related article: 11 Great Practices to Help You Hire Software Developers

At the end of the day, managers’ preferences when it comes to Java developers greatly vary. Others will choose to hire Java developers with an extensive experience and a solid skill set, while others will prefer to work with developers who, despite the lack in skills, are eager and willing to learn. Whatever your preference is, the best way to select the tech talent you want to work with is to choose the candidates who show a fair balance between hard skills and soft skills.

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