Java

Can you explain what Java Database Connectivity (JDBC) is?

Junior — Middle

IfellowAstonSimbirsoft

How is lazy loading of related data implemented using FetchType.LAZY in JPA?

What happens if you try to add a key-value pair to a HashMap where the value is null, and such a pair already exists with a fixed hashCode and equals returning true?

What is the difference between using @Spy and @Mock in testing?

Junior — Middle

IT OneIfellowСБЕР

What happens inside a HashMap when adding an element if the hashCode method returns the same value for all objects?

Explain what a ConcurrentHashMap is and how it ensures safety during parallel data access.

Junior — Middle

RevolutПередовые Платежные РешенияIfellow+3

Can you explain how transactions are implemented within the Spring Framework?

How do you implement working with dynamic queries in Spring Data JPA?

How can a large volume of data be efficiently ordered?

How does Spring manage nested transactions within a single component or method?

Does the bean with a prototype scope ensure safety in a multithreaded environment?

How to choose the appropriate bucket in HashMap for inserting an element?

Can you explain the principle of pessimistic locking and how it differs from other locking strategies?

Junior — Middle

IfellowТ-Банк

Can you explain what is meant by the Java EE platform and what it is used for?

Tell us about your experience using database migration tools like Flyway.

What methods and tools do you use to implement pagination in applications?

What happens if you add a pair with null as the key or value to a HashMap?

How do you implement adding a new element to a HashMap data structure?

How does Kafka guarantee the security and integrity of transmitted data?

Can you explain what happens when hash codes of different objects match in the hashCode() method?