Java

What transaction management methods do you know in Spring?

In Spring, by default, in which scope are beans created?

You have a microservices architecture — did you write the annotation in a specific service or for the entire project? How did you distribute the solution?

Tell me about a case of SQL query optimization: what was the problem and how was it solved?

How to practically apply annotations? Have you written your own custom annotations?

How to deal with the N+1 problem?

Code review: look at the getDivisions method (code screenshots) — what did you like, what didn't you like? Is the use of Insensitive Order sorting, error handling, streaming, etc., justified?

Explain what propagation means when a method is called from the context of an already open transaction.

What is a singleton as a design pattern?

If an entity is loaded with one request and we call a method to get a related entity — how many total requests will be made?

What levels of transaction isolation do you know?

How would you explain to another developer what Spring Data is and its value?

What is an annotation in Java? How would you explain it to another developer?

Have you used TransactionTemplate in your work? Provide an example where you programmatically decided whether to rollback a transaction or not.

Does the save() method in JPA repository create a new entity or update an existing one?

Is the use of @Transactional(readOnly=true) annotation in the method justified here?

What exception handling methods have you used in Spring Boot applications?

Task: there are two microservices, and you need to transfer a large table (3+ million records) from one to another (create a local copy). How would you implement this, considering that data may change frequently and transactional integrity (all or nothing) is required?

What parameters does the @Transactional annotation have?

Tell us about the cache you mentioned: how it was implemented, whether there were issues when working with multiple instances, and how they were resolved (including through Kafka)?