30 interview questions for Java Developers - part one

30 interview questions for Java Developers - part one

Especially for you, we decided to publish the first set of 30 Java developer questions. You will find answers to most of them in our newsletter. I invite you to read.

  1. Standard questions: Tell me what projects you participated in, what technologies you used etc.
  2. How does JIT work? Does it have any disadvantages?
  3. List the ways of dependency injection. What method are you using and why?
  4. What is encapsulation?
  5. What things came in with Java11. What were you using?
  6. Public vs. private key cryptography. What's the difference and which method is used in TLS?
  7. How would you write a controller method to remove multiple users?
  8. What is REST?
  9. What is SOAP?
  10. Microservices vs Monoliths. What are the differences?
  11. What are the indices for and what do you know?
  12. Principles of SOLID, IoC, Dependency Injection. Make them out.
  13. We have 2 websites, each of them has its own database. How to get consistency / transactional when one calls the other?
  14. Why is BigDecimal better than double to store money values? Why is double not precise?
  15. What is BindingResult for in Spring?
  16. List transaction isolation levels and explain how one of them works?
  17. The @Transactional annotation what properties / what can be set?
  18. How to validate incoming requests in REST in Spring? What error occurs when we give a string instead of an int?
  19. How would you secure the rest api?
  20. How to store passwords in the database? How does bcrypt work?
  21. What are the advantages / disadvantages of stream api in Java?
  22. How does the HTTP protocol work? What are the methods?
  23. When would you choose a data storage solution based on a relational database and when is NoSQL? What would you consider the criteria?
  24. Java memory model. What kind of Garbage Collectors do you know? What are they for?
  25. How does HashMap / ConcurrentHashMap work inside?
  26. Communication with external services. Approach to error handling. How would you handle common communication mistakes?
  27. Types of web attacks, eg xxs, csrf, list and explain one of them.
  28. How does Java Virtual Machine Work? What elements does it consist of?
  29. How is the query select * from table where id = 1 performed?
  30. What are Foreign Keys in SQL?

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