Java

What is the difference between ConcurrentHashMap and Collections.synchronizedMap?

Senior

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How was your monitoring set up? Did you have to create custom metrics and alerts?

Senior

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How to properly roll out database migrations without failures? How to delete fields?

Senior

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What to do with high database utilization? What if the database utilization is low but queries are slow?

Senior

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Why is iteration over an ArrayList collection with a million elements faster than over other data structures?

Junior — Middle

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Why is NoSQL needed? Why are relational databases insufficient? Examples of usage, advantages, storage structures.

Senior

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What is the difference between synchronized block and atomics? How does CAS work?

Senior

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What TTL should be chosen for caching rates if rates change infrequently?

Senior

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Tell me more about your implementation of CQRS in your case.

Senior

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What exactly did you tune in Kafka? Which specific parameters did you configure?

Senior

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If there is data cache, how can you determine that the cause of OOM is specifically due to it?

Senior

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Deployment problems: errors occur during deployment and disappear afterward. Why?

Senior

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package ru.tbank; @Service public class OrderService { @Autowired private OrderRepository orderRepository; @Autowired private CacheService cacheService; public Order findOrder(Long orderId) { Order order = cacheService.get(orderId); if (order == null) { order = orderRepository.findById(orderId).orElse(null); if (order != null) { cacheService.put(orderId, order); } } return order; } }

Middle+

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In what situations is the Consumer design pattern used?

Junior — Middle

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In what form did the requirements for the tasks come to you?

Middle+

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How to confirm out of memory in production and what to do about it? How to take a heap dump at the moment of OOM?

Senior

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How to ensure reliable invoice delivery if an external service might fail?

Senior

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Tell us about how tasks were distributed in your team and how architectural decisions were made.

Middle+

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Why are you looking for a new job?

Middle+

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What problems can arise when returning a JPA entity from a repository and how to avoid them?

Middle+

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