Java

What database performance improvement methods are available under high CPU load?

Junior — Middle

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Have you supported a project in production, handled incidents, monitored?

Middle+

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Why is a String object in Java immutable?

Junior — Middle

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Can you explain what is meant by a non-cumulative memory area in JVM?

Junior — Middle

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Задача Дано: CREATE TABLE profile ( id BIGSERIAL PRIMARY KEY, nickname VARCHAR, registered_at TIMESTAMP ); CREATE TABLE post ( id BIGSERIAL PRIMARY KEY, owner_id BIGINT REFERENCES profile (id), body TEXT, inserted_at TIMESTAMP, likes_count INT -- кол-во лайков ); CREATE TABLE subscription_count ( profile_id BIGINT REFERENCES profile (id) UNIQUE, followers_count INT, -- кол-во подписчиков following_count INT -- кол-во подписок ); Требуется: select p.id, sc.followers_count from post p join subscription_count sc on sc.profile_id = p.owner_id where sc.followers_count > 500 -- Индекс:create index on post (owner_id) -- Запрос:select * from post where likes_count > ? AND owner_id = ?;

Senior

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Explain the principle of optimistic locking in data management systems.

Junior — Middle

Т-БанкIfellow

When and why should you use ConcurrentHashMap instead of a regular HashMap in a multithreaded environment?

Junior — Middle

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Will an index on owner_id be used for a query with a condition on likes_count?

Senior

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How did you first start learning and using the Java programming language?

Junior — Middle

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How can optimistic locking be ensured for managing concurrent data updates?

Middle — Middle+

ProoftechСБЕРТ-Банк+1

What are the main advantages and disadvantages of using ExecutorService in Java?

Junior — Middle

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If monitoring shows that the database has started responding slowly, how will you investigate the cause?

Middle+

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How are topics and partitions related in Kafka? Is message order guaranteed across different partitions?

Middle+

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How can you determine that a service restart is due to cache updates caused by OutOfMemoryError?

Middle — Middle+

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Проводил ли ты когда-либо наблюдение за состоянием работы сервиса?

Junior — Middle

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Explain what partial indexes in databases are and in which cases they are used.

Junior — Middle

Т-БанкAston

In what cases in SQL is the command SELECT FOR UPDATE used and for what purposes?

Junior — Middle

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What is the difference between using a foreign key and directly using an identifier from another table in a database?

Junior — Middle

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I want to add an index to a table with a million records — what are the consequences and how to do it correctly?

Senior

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What methods can be used to eliminate the problem of regular server reboots caused by OutOfMemoryError?

Junior — Middle

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