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Channel

Библиотека собеса по Java | вопросы с собеседований

@java_interview_lib

On this record: Topic · Growth · Engagement · Reactions · Posts · Citations · Handles named that no longer answer · Telegram's recommendations · Cite this entry

6,361subscribers

-113 since we began measuring on 6 August 2026

Risers and fallers across the register · movement among entries of 3,162–10,000.

Register entry

Telegram ID-1001890717391
TypeChannel
Username@java_interview_lib
CreatedBetween 1 October 2022 and 30 September 2023 — estimated from Telegram’s id allocation, not measured. How this range is calculated.
First recorded6 August 2026
Last confirmed live8 November 2026
Measurements held23
Confirmed unchanged1 time, most recently 8 November 2026
On Telegramt.me/java_interview_lib

Topic

Education — a classification, not a measurement. An on-box language model (Qwen3.6-35B-A3B-FP8, prompt version 1) read this channel’s own recent posts on 12 September 2026 and assigned it the closest of 31 fixed categories, at 99% confidence. This is a model’s judgement about what the channel is likely to be about, not a fact this register measured the way a subscriber count or a view count is measured — it can be revised on a later pass, and it carries no weight anywhere else on this page. How this classification works, and the other topics.

Growth

6,3616,4746,417.56 August 2026 — 6,474 subscribers7 August 2026 — 6,474 subscribers10 August 2026 — 6,473 subscribers14 August 2026 — 6,471 subscribers17 August 2026 — 6,470 subscribers20 August 2026 — 6,468 subscribers23 August 2026 — 6,466 subscribers29 August 2026 — 6,463 subscribers1 September 2026 — 6,466 subscribers4 September 2026 — 6,468 subscribers10 September 2026 — 6,464 subscribers13 September 2026 — 6,458 subscribers17 September 2026 — 6,451 subscribers27 September 2026 — 6,433 subscribers5 October 2026 — 6,421 subscribers12 October 2026 — 6,414 subscribers18 October 2026 — 6,404 subscribers24 October 2026 — 6,394 subscribers27 October 2026 — 6,378 subscribers30 October 2026 — 6,373 subscribers2 November 2026 — 6,367 subscribers5 November 2026 — 6,362 subscribers8 November 2026 — 6,361 subscribers6 August 20268 November 2026
23 measurements spanning 94 days, net -113. Dots are measurements; the straight line between them is drawn to join them, not to claim we know the path taken in between — snapshots are recorded only when a count changes, so gaps mean “no change observed”, never “interpolated”. The vertical axis spans 6,344–6,491 and does not start at zero.
Measurement log — every subscribers count we have recorded, most recent 20 of 23
Measured (UTC)SubscribersChange
8 Nov 2026, 09:476,361-1
5 Nov 2026, 09:466,362-5
2 Nov 2026, 10:546,367-6
30 Oct 2026, 10:366,373-5
27 Oct 2026, 18:266,378-16
24 Oct 2026, 13:496,394-10
18 Oct 2026, 13:576,404-10
12 Oct 2026, 13:386,414-7
5 Oct 2026, 10:546,421-12
27 Sept 2026, 01:026,433-18
17 Sept 2026, 20:416,451-7
13 Sept 2026, 21:416,458-6
10 Sept 2026, 04:586,464-4
4 Sept 2026, 15:206,468+2
1 Sept 2026, 09:146,466+3
29 Aug 2026, 07:576,463-3
23 Aug 2026, 03:546,466-2
20 Aug 2026, 01:116,468-2
17 Aug 2026, 10:486,470-1
14 Aug 2026, 04:156,471first reading

Engagement

44 posts held, back to 22 July 2026 — the reader has not yet reached the start of this channel’s public history, so older posts may sit further back, unread. Read across 14 pages of Telegram’s post history, 20 posts per page.

ERR · 30 days
12.2%
avg views ÷ 6,361 subscribers
Avg views / post
776
23 posts measured
Reaction rate
0.315%
reactions ÷ views · ER floor
Posts in window
23
of 44 held

ERR is average views per post over the last 30 days divided by subscribers, the definition TGStat uses, so this figure is comparable with the one you will see elsewhere. It falls structurally as a channel grows: a high ERR on a small channel and a low one on a large channel describe reach mathematics, not quality. We publish the figure and the sample it came from and pass no verdict on it.

ER is defined industry-wide as (forwards + reactions + comments) ÷ views — note the denominator is views, not subscribers. Telegram’s public web preview carries views and reactions but not forward or comment counts, so the reaction rate above is the reactions term only and is therefore a floor: the true ER for this channel is higher by an amount we have not measured and will not estimate. It is computed over the 14 of 23 measured posts that carry a reaction reading, and over those same posts' views.

What these figures were computed from
WindowRolling 30 days · latest post in window 6 November 2026
Posts held44 (22 July 2026 – 6 November 2026)
Views total17,855
Reactions total37
Forwards / commentsnot exposed by the public surface — not measured, not estimated
Readings taken6 Nov 2026, 13:23 UTC

Views are a single reading per post, taken at the time above. A post published in the last day or two is still accumulating views, which pulls the 30-day average down slightly. That is a property of the standard definition rather than a fault in it, so we keep the definition rather than “correcting” the number into something nobody can reproduce.

Precision. Telegram publishes view counts on its public widget in short form — 8.12K, 3.7M — so any reading at or above 1,000 reaches us rounded to three significant figures, and only counts below 1,000 are exact. Averages and rates derived from them are shown to the same precision rather than to the unit: a figure like 3,701,250 would assert digits nobody measured.

Reaction counts are published per emoji and rounded the same way, so a total below 1,000 is exact and a larger one is a sum that may carry a rounded component from each emoji above 1,000. Because it is a sum, it does not look rounded — read a large reaction total as three significant figures per contributing emoji rather than as the figure it prints.

Reaction mix

120 reactions across 28 posts, in 10 distinct kinds. The most used accounts for 51.7% of them.

Every reaction kind recorded on the sample, most used first
ReactionCountShareShare, drawn
👍6251.7%
🔥2520.8%
❤2117.5%
😁32.50%
❤‍🔥21.67%
👏21.67%
🥱21.67%
💯10.833%
🤔10.833%
🥰10.833%

No sentiment is inferred, and none should be read in. This table is ordered by count and by nothing else. Emoji do not carry stable meaning across languages or communities — 🙏 is thanks in one channel and mourning in another — so we publish which ones were pressed and how often, and pass no judgement on what an audience meant by them.

Precision. Telegram publishes reaction counts per emoji and short-forms each one — 4.34K, 1.2M — so any single kind at or above 1,000 reaches us at three significant figures, and only counts below 1,000 are exact. The shares above are ratios of those figures and carry the same error. This is also why the total here can differ slightly from a reaction total printed elsewhere on the page: both are sums of the same rounded parts, taken over samples with different edges.

Coverage. Reactions were read on 28 of the 44 sampled posts in this sample. Summed by Telegram’s own count on each post — not by adding up the per-emoji breakdown above — those same posts carry 120 reactions in total: the kind of figure the paragraph above means by “a reaction total printed elsewhere on the page”.

Measured over the 44 most recent posts we hold, published 22 July 2026 to 6 November 2026, using the newest reading held for each. Telegram Stars are excluded: they are a payment, not a reaction, and they have their own section.

Recent posts

Telegram’s own ‘edited’ marker: 0 of 23 posts held from the last 30 days (0%) carried it when this register last read them. The marker says a post was changed after publishing, not what it said before — this register holds the earlier wording only where an edit fell between two of its own reads (see the edit ledger and how it is measured).

6 Nov 2026, 12:00 UTC188 viewsread 6 November 2026

👀 Почему ThreadLocal нужно очищать после задачи в пуле потоков? Ответ: ThreadLocal связывает значение с потоком. Рабочий поток пула может пережить множество задач, поэтому данные одного запроса способны остаться до следующего запуска на том же потоке. Если там хранится пользователь, идентификатор запроса или другой контекст, новая задача может получить старое значение. Пока значение удерживается потоком, связанный …

6 Nov 2026, 09:49 UTC286 viewsread 6 November 2026
Photo

Новый уровень ИТ-практик: Импульс Т1 снова в Москве 🚀 19 ноября столица примет ИТ-конференцию Импульс Т1. Мы создаём среду, где специалисты получают не просто полезную информацию, а рабочие инструменты, применимые в проектах уже на следующий день. Импульс Т1 2026 — это: 🔹5 направлений деловой программы; 🔹130+ экспертных спикеров; 🔹70+ прикладных активностей; 🔹2 000+ участников сообщества. Уникальный формат — учимс…

5 Nov 2026, 12:01 UTC472 views2 reactionsread 6 November 2026

👀 Освобождает ли Thread.sleep монитор и чем он отличается от Object.wait? Ответ: Thread.sleep приостанавливает текущий поток и сохраняет захваченные им мониторы. Другие потоки продолжат ждать, если им нужен тот же монитор. Object.wait освобождает монитор объекта, на котором вызван, и переводит поток в ожидание. Перед вызовом поток должен владеть этим монитором. Перед продолжением работы он снова захватывает его. w…

👍2

4 Nov 2026, 12:01 UTC562 views1 reactionsread 6 November 2026

Почему в List<? extends Number> нельзя добавить Integer? Ответ: Точный тип элементов неизвестен. За такой ссылкой может находиться, например, List<Double>. Если разрешить добавить Integer, типобезопасность нарушится. Читать элементы можно как Number, потому что верхняя граница известна. Для коллекции, в которую нужно добавлять целые числа, часто подходит List<? super Integer>. Отдельный случай — null: система типов …

👍1

3 Nov 2026, 12:05 UTC632 views4 reactionsread 6 November 2026

Может ли return в finally скрыть исключение из try? Ответ: Да. Если try выбросил исключение, а finally завершился через return, метод вернёт значение из finally. Исходное исключение не продолжит распространяться. Аналогично новый throw в finally может заменить прежнюю ошибку. Поэтому в finally лучше оставлять очистку ресурсов и избегать команд, которые меняют способ завершения метода. Для закрываемых ресурсов обычно…

👍4

2 Nov 2026, 12:05 UTC724 views1 reactionsread 6 November 2026

Блокируют ли друг друга static synchronized и synchronized-метод экземпляра? Ответ: Сами по себе — нет. Статический метод захватывает монитор объекта Class, а метод экземпляра — монитор this. Это разные блокировки, поэтому два метода могут выполняться одновременно. Если они работают с одними данными, наличие слова synchronized в обоих ещё не обеспечивает защиту. Для согласованного доступа все участники должны исполь…

👍1

1 Nov 2026, 12:05 UTC762 viewsread 6 November 2026

Чем thenApply отличается от thenCompose? Ответ: thenApply преобразует полученное значение. Если функция вернула ещё один CompletableFuture, результатом будет вложенная конструкция — future внутри future. thenCompose нужен, когда следующий шаг сам возвращает CompletionStage. Он связывает этапы и возвращает одну общую стадию с конечным результатом. Выбирайте thenApply для обычного преобразования, а thenCompose — для п…

31 Oct 2026, 12:03 UTC773 viewsread 6 November 2026

Почему TreeSet может не добавить объект, который не равен существующему по equals? Ответ: Для TreeSet совпадение определяется результатом compareTo или переданного Comparator. Если сравнение возвращает ноль, коллекция считает элементы одинаковыми. Например, компаратор только по возрасту не позволит сохранить двух разных людей одного возраста. Чтобы коллекция соблюдала обычный контракт Set, порядок сравнения должен б…

30 Oct 2026, 12:04 UTC788 viewsread 6 November 2026

Запомнит ли HashMap.computeIfAbsent результат null? Ответ: Нет. Если функция вычисления вернула null, новая запись не добавляется. При следующем вызове для того же отсутствующего ключа функция может выполниться снова. Поэтому возвращать null как признак «проверили, ничего не нашли» недостаточно для кэширования отрицательного результата. Для него нужен отдельный маркер или другой способ хранения. Если ключ уже связан…

29 Oct 2026, 12:02 UTC818 views3 reactionsread 6 November 2026

Гарантирует ли Future.cancel(true), что задача остановилась? Ответ: Нет. Если задача уже выполняется и реализация поддерживает прерывание, cancel(true) пытается прервать выполняющий её поток. Но прерывание — сигнал, а не принудительная остановка. Код должен на него реагировать: проверять флаг или корректно обрабатывать InterruptedException. Успешная отмена Future не доказывает, что работа уже прекратилась. У Complet…

👍3

28 Oct 2026, 12:01 UTC820 views1 reactionsread 6 November 2026

Делает ли final объект неизменяемым? Ответ: Нет. Для переменной ссылочного типа final запрещает присвоить другую ссылку. Состояние самого объекта при этом может меняться. Например, в final List<String> items можно добавлять элементы, если реализация списка это разрешает. Чтобы объект был неизменяемым, нужно отдельно продумать его поля, методы и доступ к вложенным объектам. Одного модификатора final недостаточно. До…

👍1

28 Oct 2026, 08:18 UTC715 viewsread 6 November 2026
Photo

Приглашаем на Java Jam — бесплатный митап ЮMoney для бэкенд-разработчиков 🔥 ✅ 29 октября, четверг, 19:00 МСК — приходите на митап в Санкт-Петербурге или смотрите трансляцию. Спикеры из ЮMoney и Сбера выступят с докладами: 🟣 Один апгрейд — больше сотни сервисов: как мы обновляем Java-стек в компании Обсудим, как обновить Gradle, Spring Boot и Java в 120+ компонентах, не останавливая разработку. Расскажем, как выстр…

Showing the 12 most recent of 44 posts we hold for @java_interview_lib. View and reaction counts are the latest single reading for each post, not a live figure, and a recent post is still accumulating both. A view count marked ≈ was rounded by Telegram before we ever saw it — t.me prints views in full below 1,000 and to three significant figures above, so ≈1,200,000 means somewhere between 1,150,000 and 1,249,999. Unmarked counts are exact. Text is reproduced from the public post preview and truncated for length.

Forward network

Republished by

Channels on the register that have forwarded this channel's posts into their own feed.

Republishes

Channels on the register whose posts this channel has forwarded.

Built only from forwarded posts we have actually read, on both sides. Coverage is early and deliberately incomplete: a missing link means we have not read the post that would prove it, never that the relationship does not exist. Counts are distinct forwarded posts observed, so they only ever go up as we read more.

Mentions

Named by 6 registered channels — every channel on the register whose own posts have named this one, by its current username or any other username it currently holds, merged from two separately captured readings of the same fact so a namer caught by only one of them is not missed and a namer both caught is not counted twice. A username this channel has since dropped is not matched — that handle may belong to someone else now, and crediting today’s namer to yesterday’s owner would misattribute it.

A mention is a weaker signal than a forward and is counted separately for that reason — naming a channel is not republishing it, and a handle in a post body is easy to place deliberately. The post counts beside each row below are distinct posts in which the handle appeared, from posts we have read on both sides — the “Named by N registered channels” figure above is a different count, of distinct NAMING CHANNELS rather than posts, and is not the sum of the rows under it.

Appears in Telegram’s recommendations for other channels

The reverse of the list above, and a different kind of signal. This does not require this channel to have ever been asked about directly — each row below is a channel we DID ask Telegram about, whose Telegram-generated list happened to include this one. A channel can appear here with an empty list above it, because being named by someone else’s query is independent of having been queried itself.

Библиотека джависта | Java, Spring, Maven, Hibernate
@javaproglib · 21,780
Telegram ranks this channel #1 of 88 here — alongside 87 others — read 21 September 2026
Senior Java Developer
@seniorjavist · 20,368
Telegram ranks this channel #22 of 89 here — alongside 88 others — read 26 September 2026
Java библиотека
@javalib · 30,300
Telegram ranks this channel #22 of 84 here — alongside 83 others — read 7 September 2026
Библиотека программиста
@proglibrary · 77,612
Telegram ranks this channel #77 of 82 here — alongside 81 others — read 19 August 2026

This channel appears in 4 seed channels' Telegram-generated recommendation lists in total. Each is Telegram’s list for THAT channel, not this one — see how this is measured.

Cite this entry

A live page changes as we take new readings, so a citation should name the measurement it is based on, not just the URL. The line below cites the subscriber count as measured 8 November 2026 — this entry's latest reading, not the date you are reading this.

“Библиотека собеса по Java | вопросы с собеседований” (@java_interview_lib), 6,361 subscribers as measured 8 November 2026. Telegram Register, tgregister.com/channel/java_interview_lib.

Full measurement history, CC BY 4.0. Every reading this register holds for this entry, not just the latest one, as a dated, downloadable record: CSV · JSON. Free to use with attribution to tgregister.com. Each file carries its own generation timestamp, which is the figure to cite for exactly when the data was retrieved.