Preparation for a Java Developer Interview

Our experts have over 20 years of experience in programming, recruiting, and training Java specialists at NIX. During this time, they have conducted hundreds, even thousands, of interviews. Today, we want to provide you with some tips on how to successfully ace an interview for a Java Developer position. Whether you are a novice developer, an experienced professional, or someone looking to transition into IT, this information will be invaluable to you.

Java offers an excellent entry point for a career in software development. Why is that?

First and foremost, Java is more than just a programming language. It is a technology and a platform that allows for the development of complex applications.

With Java, you can create applications for embedded systems, mobile devices, and desktops. However, the majority of software applications are large-scale, enterprise-level distributed systems. This is mainly because of the language’s widespread usage, its maturity, the availability of numerous open-source libraries, frameworks, and development tools, and the huge community. Many of these systems are entirely written in Java or utilize components based on this technology. Furthermore, future projects are likely to continue using Java. Hence, the demand for Java specialists is expanding and will continue to grow for years to come.

Additionally, Java is constantly evolving. Its syntax introduces constructs that simplify code writing, while mechanisms are added to enhance application performance and security. The Java development community continuously creates new frameworks and libraries, incorporating modern approaches to application design.

Java development requires a strong technical background

The specifics of large distributional applications cause a rather high entry barrier. To succeed in Java, you need to have a deep understanding of computer science, including:

• Data structures
• Algorithms
• System principles, computer architecture, and data storage
• Computing theory
• Data storage and processing
• Databases
• Software development technologies

Furthermore, knowledge of mathematical disciplines such as combinatorics and probability theory is important. These subjects are typically covered in core technical university programs. However, if your education is not in a related field, don’t worry. It doesn’t mean that the path to IT is closed for you. With determination, persistence, and diligence, you can acquire the necessary knowledge and skills.

Over the years, we have encountered many individuals with diverse backgrounds who have built successful careers as programmers.

A developer’s journey is a lifelong process of learning. If you stop acquiring new knowledge and skills at any point, your career will stagnate.

Tips for Those Considering a Career in IT

First and foremost, you will need to acquire knowledge of computer science and develop an understanding of the Java language, as these will be instrumental in mastering various aspects of computer science, such as data structures and algorithms.

There are several ways you can acquire this knowledge. You can read books, watch instructional videos on YouTube, or enroll in online or offline courses. Each approach offers its own benefits, and it’s important to assess which option works best for you.

We recommend starting with the most readily available resources. When selecting books or YouTube videos, keep in mind that English proficiency will likely be required. In general, English language skills are as important as programming itself. Most technical documentation, training videos, and online courses are in English. Furthermore, the project requirements you will eventually work on are likely to be in English as well.

It’s advisable to learn a foreign language even before diving into programming.

Another viable option for acquiring the necessary knowledge is to join an IT company that offers training programs and potential internships or job opportunities. In such cases, you can be assured of receiving quality training, as experienced developers will guide you in preparation for work within their company. Additionally, this path may streamline the acceptance process, as successful completion of the training program can potentially exempt you from the interview stage.

At NIX, we have a program specifically designed for aspiring Java developers who lack foundational knowledge.

Once you have obtained the necessary knowledge, you can proceed to the next step in your journey.

Tips for people who want to become a Java Developer

As we have mentioned above, the barrier to entry for developing large systems in Java is quite high. Even simple tasks may require the ability to work with several technologies, frameworks, and libraries. Moreover, the set of these conditions can change radically from project to project. Keeping this in mind, IT companies that hire developers without experience additionally train young specialists to work on projects that are currently in use.

You should not be afraid to try yourself for such jobs, even without extensive knowledge. But remember that your basic knowledge must be strong enough.

Tips for Java Developer Resume

Having a well-crafted resume is often necessary when searching for a job. While some companies may provide online questionnaires on their websites as an alternative, it is beneficial for job seekers to create their own CV. This document allows you to showcase information about yourself that highlights your strengths and sets you apart from other applicants for the same position.

Considering that you may currently lack professional experience, it’s important to emphasize your non-technical skills.

Some key soft skills to highlight include:

• Self-learning abilities
• Teamwork experience
• Independence
• Friendliness
• Ability to overcome challenges
• Communication skills
• Diligence
• Responsibility

Describe all your positive traits in your CV, focusing on these areas. Fluency in English and proficiency in other foreign languages are also important points to mention.

If you have work available in a GitHub repository, be sure to include a link to it in your resume. This serves two purposes:

1. It demonstrates your familiarity with version control systems.
2. It showcases the quality of your code and provides evidence of your coding experience.

Keeping the code you write during training in a public repository is always a good idea.

Although, don’t forget to include your profession and the university you graduated from, or the course you are currently studying. Additionally, providing information about any online or offline courses, or IT schools where you gained technical knowledge, will be useful. It’s worth noting that if you mention that you have completed multiple courses where you learned the basics of a programming language, but are unable to answer basic questions during an interview, technical experts may question your ability to learn effectively.

By incorporating these tips, you can create a compelling resume that showcases your strengths and demonstrates your commitment to professional growth.

What to Expect from Java Developer Interview?

Moving from the resume to the job interview, it’s important to note that sending a resume or questionnaire online doesn’t always guarantee an immediate invitation for an interview. In cases where there is a high volume of applicants seeking developer positions, experts and recruiters may introduce a technical testing stage to filter out candidates who lack the required knowledge.

The NIX test typically consists of straightforward questions about Java basics and object-oriented programming. Additionally, an English proficiency quiz is often included. If an applicant successfully passes both tests, they are then invited for an interview.

During the interview, be prepared to answer questions regarding the information presented in your CV or questionnaire. If you have limited practical experience, the experts may start with technical inquiries right away.

In our opinion, a Junior Java Developer applicant should:

• Have a clear understanding of object-oriented programming principles.
• Be familiar with basic libraries in the JDK, such as collections, I/O, and multithreading.

We also assess your knowledge of internet concepts and fundamental computer science. Having additional knowledge of interacting with databases, basic frameworks (Spring, Hibernate), and working with build tools (Maven, Gradle) is considered a bonus.

The interviewer’s goal is to gauge the candidate’s knowledge on specific topics, which often leads to follow-up questions after the initial response. Even if an answer is incorrect, the interviewers may ask leading questions to understand the candidate’s thought process and ability to draw conclusions.

Many job interviews require candidates to write code to solve specific tasks. We understand that interviews can be stressful, potentially affecting thought processes. Therefore, we prefer to discuss the candidate’s answers calmly, sometimes with humor. The coding ability is often assessed during the candidate’s internship with the team.

Outcome of the interview

The result of the interview is influenced by the correctness of answers to technical questions, as well as the overall impression of the candidate’s communication skills. We aim to evaluate how well the applicant would fit within our team. In some cases, a candidate may not answer technical questions perfectly but leave a positive impression. In such instances, we may schedule a second interview in a week or two, allowing the candidate time to improve their knowledge on necessary topics.

After the experts have concluded their questioning, the job seeker is given an opportunity to ask questions as well. These can include inquiries about the terms of cooperation, projects the candidate will be involved in, and potential career prospects at the company.

If you do not succeed in your job interview, we advise you not to be discouraged. It serves as an opportunity to improve your skills and try again.

Remember: Technical answers are not the sole criteria for receiving an offer. Fit within the team is also taken into account. If you don’t fit that criterion (and you likely won’t be explicitly told so), it simply means that it’s not the right team for you. Your team is still waiting for you elsewhere.

Tips for Experienced Java Developers

Recruiting experienced developers differs from recruiting beginners. In this case, we place significant emphasis on work experience, the projects the person has been involved in, and their areas of responsibility. While knowledge of specific technologies is important, it is not the sole deciding factor. Each new project brings a unique set of technologies and frameworks.

An experienced Java developer is expected to quickly adapt to unfamiliar technologies and easily acquire the necessary skills to tackle the tasks at hand.

What interview questions to expect?

During the interview with an experienced developer, we ask a few targeted questions about the fundamentals and main frameworks. We once had a case where an applicant immediately stated that they would not answer simple questions. This behaviour seemed odd since it was our first meeting. We expect a certain level of knowledge from candidates, and refusing to demonstrate it raises concerns. In that instance, we ended the interview promptly. It was the shortest interview we have ever conducted.

If the answers to the basic questions demonstrate the candidate’s understanding of the subject matter, we move on to discussing the projects listed in their resume. At this stage, there are no strict rules.

We are interested in how the person approaches problem-solving. During job interviews, we may describe a specific problem situation and ask the candidate to identify its possible source. This allows us to assess the depth of their experience and their ability to make decisions when faced with limited information.

Throughout the conversation, we try to determine how well the candidate will integrate into the team. The company typically recruits an experienced developer for a specific project and position, with defined knowledge requirements and level of responsibility.

The most important advice for experienced individuals attending an interview is to come prepared. It may seem obvious, but you should be ready to answer any technical question related to the experience listed on your CV. It’s better not to improvise on the spot. As an experienced developer, you should have a deeper understanding of the tools you work with beyond the immediate tasks at hand.

If you consciously decide to attend a job interview at a particular company, make sure you familiarize yourself with the team’s work, their products, and their clients. This knowledge will undoubtedly influence the questions you are asked.

Conclusion

It’s an opportune time to build a career in IT, especially in the field of Java. The market is expanding, there is a shortage of skilled professionals, and numerous options are available for acquiring knowledge. This provides excellent prospects for career growth. So, be confident and bold! We wish you success in your interviews, exciting projects, and great teams.

Topics and materials to get ready for the Junior Java Developer interview

To gain a fundamental understanding of Java programming, we recommend beginners to explore the following topics and materials:

Object-oriented programming:

• Polymorphism
• OOP Principles

Java Basics:

• Java (JDK, JVM, JRE, compiler) 
• Data Types 
• The primitives 
• Type conversion 
• Logic / Math operations 
• Reference Types 
• Arrays 
• String handling 
• Conditional statements 
• Cycles
• Exceptions 
• Classes, Objects, Interfaces
• Collections 
• What’s new in Java 8?
• Input/Output 
• Multithreading 
• Working with Database, JDBC 
• Servlet API

Java frameworks, libraries and tools:

• Maven 
• Git 
• Hibernate 
• Apache Commons 
• Apache Tomcat

Spring:

• Web
• Data 
• Security
• Boot

Databases:

• MySQL
• PostgreSQL
• MongoDB 
• H2

Customer environment:

1. HTML 

2. CSS: 

• Cascading Style Sheets, level 1 
• Cascading Style Sheets Level 2 Revision 1 
• CSS Snapshot 2018 

3. JavaScript 

• Modern JavaScript Tutorial
• The Progressive JavaScript Framework 
• jQuery

Books:

• J. Glenn Brookshire, Denis Brilov “Computer Science. A Basic Course, 13th Edition”
• Kay Horstmann, “Java. The Professional’s Library.”
• Bob Martin “Clean Code: Creation, Analysis, and Refactoring”. 
• Joshua Bloch, Effective Java. 3rd Edition
• Vladston Ferrero Philo “A Theoretical Minimum in Computer Science”