A team is a core of any software project. Are you, as the employer, just giving lip service to this concept or affirming these words indeed? Surely, you would like to have the best developers in your team. You will have a job to find the right candidates. This calls for strong interviewing and recruiting competencies. Let’s figure out how to screen Java developer skills not to be sorry about your choice.
First off, you should think about a comprehensive and accurate job description that will communicate your Java project goals to potential employees. So, a good job description must contain the following points:
- Job title
- Job roles and responsibilities
- Objectives of the project. What do you expect from the candidates?
- Perspectives of career growth
- Soft skills
- Technology stack required
- Some words about the company’s culture
These are just main aspects you should definitely include into your description to avoid initial misunderstanding and a bunch of irrelevant CVs sent to you.
Hire the Best Java Developers: The Golden Rules of In-Person Interviews
Beyond sorting resumes and phone screening, there are in-person interviews which are face-to-face meetings with your candidates. Below are some tips that can help you craft the best-recruiting strategy for your company.
Rule 1 – No entry, non-programmers!
When it comes to hiring technology experts you need to understand how strong their programming and tech skills are. Managers will hardly measure and access effectively these skills. Thus and so other developers act as peers during an in-person interview. To ensure objective screening of potential employees you will need to engage at least 4-5 developers into the process. Each of the peers should be able to access the candidate’s skills and give a short summary of those. It is recommended that only senior team members have the right to reject the applicant in case they think that the candidate is not worth hiring.
Rule 2 – Easy does it!
To recruit Java developers that fit your project needs and goals, build in time for an unhasting face-to-face interview. You will hardly make a decision if you spend less than an hour for a conversation with a candidate.
Rule 3 – Sort your candidates out!
Professionals like Joel Spolsky, co-founder of Trello, distinguishes three types of programmers:
- The 1st type of potential employees lacks the basic skills for doing the required job.
- The 2nd type of people is superstars or computer geeks.
- The third type is a sort of “maybe” candidates.
According to this scale, you can define “yes”, “no”, and “maybe” candidates.
Rule 4 – Be accurate in your decisions!
If a person ticks all the boxes and meets all your hiring criteria don’t hesitate to hire. In case you see a developer has no basic knowledge and skills, say “no” without any doubts (unless you will teach this person yourself). Be careful with such expressions like “I would hire but not for this project” or “Hire but not today”. Just say “no” in case you are doubting.
To sum it up, your task is to hire Java developer who knows how to get things done. Remember, your job interview must flow so that a candidate can show you how smart he/she is. Let people talk about their expertise and experience. Give them problems to solve during a conversation. A person will be able to demonstrate his problem-solving skills.
Top Interview Questions for a Java Developer
To recruit Java developers you should make a list of the questions that are closely connected to the technology. However, we have prepared standard questions you can ask:
- Provide a clear introduction about your company and project. Introduce yourself and tell how you see a person go about solving issues.
- Ask your candidate about previous work experience if available. If you talk to a college graduate student ask about his thesis paper or a major subject. Note that some candidates can’t talk about their previous projects in detail as they signed NDA agreements.
- Give a simple programming problem for your candidate to solve. Let it be a problem that can be solved by a developer who is writing code in any of the existing programming languages.
- Ask a tricky question that can demonstrate how smart a person is in problem-thinking and solving algorithms.
- Ask a person if he has any question for you. People who are passionate about what they are doing will always have a lot of brilliant questions to ask.
What Questions to Avoid During an Interview?
Avoid asking the questions that might build a preconceived conclusion. Surely, your full stack Java developer interview questions shouldn’t include brain teasers. Such types of questions take to much time. Besides, those can be misinterpreted by both interviewers and interviewees.
How Much Time Does It Take to Decide on a Candidate?
Some companies give a feedback or a short summary of the interview during a few days or even weeks. However, some experts consider that the best time to decide on a person is 3 minutes after the end of a conversation. It will take you around 15 minutes to take a final decision and respond to the person you screened.
What Are Round Interview Questions?
As we wrote, you may engage 4-5 developers to screen the skills of a potential candidate. It means you will inevitably interview the applicant during a few rounds. First-round questions are rather general questions than specific technology issues. Second-round questions are more specific, technology-focused and concerning the ongoing project. Below are some sample core Java interview questions for experienced developers provided by our experts. These questions will clue how to screen Java developer skills like a pro.
What Are the Most Popular Experienced Java Developer Interview Questions?
Second-round questions list must be made with regard to a Java developer experience. The higher the experience is, the harder questions should be asked. According to Interview Mocha, Java competencies can be evaluated with the help of SME (subject matter expertise) questions concerning the general aspects of the entire stack or a stand-alone concept. Below is the chart that includes the Java-based stacks and frameworks that can become a subject of your face-to-face meeting with a job applicant.
Interview Mocha divides Java developer 3 years experience interview questions into the following categories:
- Behavioral aspects
- Tricky questions
As you see, the rounds are much the same as we mentioned above. Along with developers, candidates to a Java job position can be interviewed and screened by project managers and CEOs. Below there are some typical topics they discuss.
3 Sample Questions with Answers Provided by our Java Developer
What is method signature in Java?
Combination of method name and types of its parameters. The class cannot contain two methods with the same signature.
What is the difference between <? extends CharSequence>, <? super CharSequence>, and <CharSequence>?
* <? extends CharSequence> is used when intent of type declaration is to only read values of type CharSequence,
for example List<String> can be used where List<? extends CharSequence> is required because String extends CharSequence, or if method has generic return type of <? extends CharSequence>, then it can be overridden to return concrete type that extends CharSequence, like String, StringBuilder, etc. This is also called “type co-variance”.
* <? super CharSequence> is used when intent of type declaration is to write values to it and do not read,
for example Collection<Object> can be used where Collection<? super CharSequence> is required.
This is also called “type contravariance”.
* <CharSequence> is used when declared type will be used for reading and write because allowing type variance for such use cases would lead to type errors (reading Object when CharSequence is required, or storing String where StringBuilder is required, etc.), the type is fixed. This is also called “type in-variance”.
What does the term “happens-before” mean in Java?
If it’s said that A happens-before B, it means that changes in memory made by A will be visible to B when it gets executed.
Project Manager Round Interview Questions for Java Developer
Project manager interview round can be as daunting as the second round. Here PMs can ask Java developers the following questions:
- Questions about technology innovations and trends.
- Specifics of the project/work.
- Questions defining candidate’s leadership qualities, commitment, and success orientation.
There are a lot of other things project managers ask. According to the answers of the applicants, PMs analyze how good they fit the job offered. Usually, a conversation may start with a general introduction followed by more specific topics about behavioral aspects and the willingness to be completely involved in a new project. It is important for PMs to understand whether a person is a team player because project’s success depends greatly on how a team works closely together. Time management skills can also become a subject of the interview as these skills define how productive a person is at a workplace.
Top 15 Most Frequent Simple Questions to Ask a Java Developer during an Interview
- Explain what an object is.
- What is method overriding?
- Super keyword explained.
- What is method overloading?
- What are the main differences between C++ and Java?
- Explain what a JIT compiler is.
- What is bytecode?
- Explain the difference between method overloading and method overriding.
- Abstract class vs. interface.
- Why Is Java platform independent?
- What are static blocks and initializers?
- What is a constructor in Java?
- Explain the difference between Character Constant and String Constant.
- What is ASCII Code?
- What is Unicode?
To sum it all up, note, you need smart people who know how to complete the tasks. You should be 100 percent sure about your decision on the person of your choosing. If your team has any tips and tricks on employing developers feel free to share those with our readers in the comments below.