Programmers world

Java recruitment questions and tasks. Interview step by step

Looking for a job can be a challenge at any stage of one’s career, especially when the candidate is just about to enter the labor market. That statement also applies to Java programming language. That is because it is used in many companies from all around the world. You can complete Java recruitment process with no problems at all, provided it was preceded by proper preparations. Discover the most common interview questions for junior programmers and interns and find your dream Java job!

Java: interview questions for junior programmers and interns

Core Java interview questions for junior programmers and interns often consist of purely theoretical definitions. Such recruitment tasks tend to include elaborating on a definition of a particular mechanism or tool and giving an example of its use. Moreover, one should also be familiar with good practices related to those concepts. Frameworks commonly used as a basic technological stack for a Java programmer are also important. Those Java interview questions often include definitions such as:

  • Immutable objects
  • Software design patterns
  • Threads
  • Exceptions
  • Garbage Collector
  • Concepts related to Java 8+
    • Stream
    • Functional interface
    • Lambda
    • Optional
  • TDD
  • Spring
    • What is Spring?
    • Common Spring modules
    • Dependency Injection mechanism
    • Methods for Bean creation
  • Hibernate/JPA
    • EntityManager
    • Adnotations related to creation and configuration of entities
      • Column
      • Entity
      • ManyToMany
        • Join Column
      • REST API
        • REST – Representational State Transfer
        • Basic HTTP/HTTPS protocol methods used for object operations
        • Principles of URL creation
        • HATEOS

Prospective Java programmers are often required to have a knowledge of databases. For example, relational databases are fairly common here. However, the number of offers involving graph databases and non-relational databases, such as MongoDB, is also on the rise.

Java interview questions can also include other definitions related to the particular project or a position a candidate applies for. Thus, before the meeting it is worth to expand one’s knowledge of Java related concepts, such as encapsulation, polymorphism, serialization or recursion. Those questions can also appear during an interview!

Java recruitment process: sample interview questions 

The sole theory is yet not enough to be successful in programming. Java interview often involves a series of questions on practical knowledge of that programming language. Differences between two different concepts and tools are especially common here. This type of Java recruitment questions usually involves the comparison of definitions such as:

  • List, map and set
  • LinkedList and ArrayList
  • Abstract class and interface
  • Equals() and “==”;
  • JDK, JRE and JVM
  • Hashtable and Hashmap
  • Checked and unchecked exceptions
  • Override and overload
  • Throw and throws and their use
  • A+=b and a=a+b operations

Common Java recruitment questions also include all types of divisions used in this programming language. During an interview a question on numeric types, levels of tests, types of design patterns, exceptions, loops and collections may appear. What is more, recruiters often tend to ask candidates about the meaning or the use of particular code fragments.

Java recruitment tasks. What problems you may have to solve?

Java interview often consists of not only questions, but also recruitment tasks that have to be solved by a prospective programmer. Those tasks are usually related to the project a candidate wants to join. Thus, it is worth to take a closer look at it during the early stages of recruitment process or right before the meeting by looking at the details of the project on the Internet.

However, there are a few types of Java recruitment tasks that have a significant chance of appearing during an interview. Usually they involve writing a few lines of code solving a problem given by the recruiter. That exercise requires a candidate to come up with an idea that can be further forged into an algorithm. For example, an algorithm for displaying a series of prime numbers can appear here. Creating a simple app (I.e. for processing the data stored in a collection) is also a common recruitment task for Java Programmers. The shorter tasks usually involve predicting a chance for a compilation of given code or predicting the outcome of that compilation. Practical use of common Java concept, such as recurrence, is also a part of many recruitment questions.

Java recruitment process: what else may come in handy?

Java interview is not all about writing the code. A knowledge of English language can also be a huge advantage for a candidate. Many IT companies operate in an international environment, what makes a bilingualism a basic requirement for prospective employees. Recruiters also pay attention to candidate’s way of thinking and his reaction to a stressful situation. They often tend to brainstorm some ideas with a candidate to see the results of such an analysis. That helps them assess candidates in terms of further potential cooperation, pair programming and other teamwork activities.

Another additional advantage, though highly depending on the project a candidate wants to join, are all the other technologies used alongside Java in programming. Version control systems and code verifying processes are the most common here, as they are widely used by programmers in their everyday work.


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