Java

How are parameters passed to methods in Java — by reference or by value?

What are the @Primary and @Qualifier annotations used for in Spring?

What is the N+1 problem in Hibernate and how to solve it?

Tell me about Inversion of Control and Dependency Injection.

Tell me about the garbage collector in Java.

What is the difference between stack and heap in Java? Where are strings stored?

What will this test output? @Test public void test50() { List<Integer> numbers = List.of(1, 2, 3, 4, 5); numbers.stream() .map(x -> { System.out.println(x); return x; }) .filter(x -> x > 2) .map(x -> { System.out.println(x); return x; }) .toList(); }

Tell me about race condition.

How to swap the values of two variables without using a third variable?

Tell me about the Strategy pattern.

What is WebSocket? What is it used for?

Tell me about Kafka: the main components on the Java side.

Tell me about Spring Security: filter chain, SecurityContext, JWT authentication.

When might the @Transactional annotation not work?

What cache types of beans have you used in Spring? What is the purpose of the prototype?

SELECT id, total, (SELECT SUM(hours * rate) FROM invoice_lines WHERE invoice_id = invoices.id) AS actual_sum FROM invoices WHERE total <> (SELECT SUM(hours * rate) FROM invoice_lines WHERE invoice_id = invoices.id);

Tell me about Gradle and Maven build tools. Which one have you worked with more?

What collections do you know? Tell about the main implementations of List. How does ArrayList differ from LinkedList?

Что такое дженерики и для чего они используются?

What is the purpose of the 'final' keyword in Java (for fields, classes)?.