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Channel

Java Books

@java_library

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

14,224subscribers

-34 since we began measuring on 6 August 2026

Risers and fallers across the register · movement among entries of 10,000–31,623.

Register entry

Telegram ID-1001695882993
TypeChannel
Username@java_library
CreatedBetween 1 December 2021 and 30 April 2023 — estimated from Telegram’s id allocation, not measured. How this range is calculated.
First recorded6 August 2026
Last confirmed live27 September 2026
Measurements held34
Confirmed unchanged1 time, most recently 27 September 2026
On Telegramt.me/java_library

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 10 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 why it has no browse page of its own yet.

Growth

14,21114,25914,2356 August 2026 — 14,258 subscribers6 August 2026 — 14,258 subscribers6 August 2026 — 14,256 subscribers7 August 2026 — 14,258 subscribers8 August 2026 — 14,259 subscribers9 August 2026 — 14,256 subscribers10 August 2026 — 14,258 subscribers12 August 2026 — 14,257 subscribers13 August 2026 — 14,258 subscribers15 August 2026 — 14,255 subscribers16 August 2026 — 14,252 subscribers17 August 2026 — 14,250 subscribers18 August 2026 — 14,242 subscribers19 August 2026 — 14,240 subscribers20 August 2026 — 14,234 subscribers21 August 2026 — 14,238 subscribers23 August 2026 — 14,235 subscribers25 August 2026 — 14,217 subscribers26 August 2026 — 14,211 subscribers27 August 2026 — 14,214 subscribers28 August 2026 — 14,215 subscribers29 August 2026 — 14,218 subscribers30 August 2026 — 14,215 subscribers31 August 2026 — 14,217 subscribers1 September 2026 — 14,234 subscribers3 September 2026 — 14,242 subscribers4 September 2026 — 14,243 subscribers7 September 2026 — 14,244 subscribers10 September 2026 — 14,241 subscribers12 September 2026 — 14,238 subscribers14 September 2026 — 14,230 subscribers15 September 2026 — 14,226 subscribers17 September 2026 — 14,222 subscribers27 September 2026 — 14,224 subscribers14,2246 August 202627 September 2026
34 measurements spanning 52 days, net -34. 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 14,204–14,266 and does not start at zero.
Measurement log — every subscribers count we have recorded, most recent 20 of 34
Measured (UTC)SubscribersChange
27 Sept 2026, 12:4114,224+2
17 Sept 2026, 19:1514,222-4
15 Sept 2026, 16:0114,226-4
14 Sept 2026, 01:2214,230-8
12 Sept 2026, 10:4214,238-3
10 Sept 2026, 06:1814,241-3
7 Sept 2026, 03:1714,244+1
4 Sept 2026, 09:4014,243+1
3 Sept 2026, 00:3614,242+8
1 Sept 2026, 21:3514,234+17
31 Aug 2026, 20:2614,217+2
30 Aug 2026, 18:1614,215-3
29 Aug 2026, 21:1614,218+3
28 Aug 2026, 23:1414,215+1
27 Aug 2026, 21:1814,214+3
26 Aug 2026, 18:4314,211-6
25 Aug 2026, 15:1214,217-18
23 Aug 2026, 02:0414,235-3
21 Aug 2026, 16:2214,238+4
20 Aug 2026, 17:2314,234first reading

Engagement

27 posts held, back to 12 May 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 55 pages of Telegram’s post history, 20 posts per page.

ERR · 30 days
3.36%
avg views ÷ 14,224 subscribers
Avg views / post
478
1 post measured
Reaction rate
1.05%
reactions ÷ views · ER floor
Posts in window
1
of 27 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.

What these figures were computed from
WindowRolling 30 days · latest post in window 2 September 2026
Posts held27 (12 May 2026 – 2 September 2026)
Views total478
Reactions total5
Forwards / commentsnot exposed by the public surface — not measured, not estimated
Readings taken2 Sept 2026, 18:54 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

140 reactions across 22 posts, in 7 distinct kinds. The most used accounts for 42.9% of them.

Every reaction kind recorded on the sample, most used first
ReactionCountShareShare, drawn
👍6042.9%
❤5740.7%
🔥1510.7%
🤔32.14%
🥰32.14%
👎10.714%
👏10.714%

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 26 of the 27 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 192 reactions in total: the kind of figure the paragraph above means by “a reaction total printed elsewhere on the page”.

Measured over the 27 most recent posts we hold, published 12 May 2026 to 2 September 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.

Advertising

Ad load
11.1%
3 of 27 posts carry an ad marker
Regulatory tokens
3
posts carrying an erid · 3 distinct tokens
Median views · ads
1,400
over 3 measured posts
Median views · rest
2,340
over 24 measured posts

An ad marker, not a judgement about a post. A post is counted here because it carries one of two explicit markings: an erid token, which Russian law has required on paid placements since 2022 and which is issued against a specific advertising contract, or a #реклама / #ad hashtag in the body, which is the channel declaring it itself. The first is documentary; the second is a self-declaration and is weaker. No classifier reads the text and decides — nothing on this site guesses that a post is an advertisement.

This is a floor, and it can only ever be a floor. A channel that runs paid placements without marking them produces no marker for us to count, and an unmarked ad is indistinguishable from an ordinary post on the public surface. The ad load above therefore means “the share of posts that declared themselves”, never “the share of posts that were paid for”. A low figure is not evidence of a channel that runs few ads.

Both figures are medians, and no ratio between them is published. Each is a view reading that actually occurred on a post, picked by percentile_disc rather than averaged, so one viral post cannot move it and no interpolated value is invented between two readings. The sample on one side is under five posts, which is too thin to compare. The two figures are shown side by side with the count behind each, and deliberately not divided into a headline like “ads get x% fewer views” — an arithmetic that is easy to print and, at this sample size, means nothing.

Advertising tokens recorded on this entry
eridPostsFirst seenLast seen
2VtzqvSBEDR122 August 202622 August 2026
2VtzqvimBRf126 August 202626 August 2026
2VtzqwyW4fK12 July 20262 July 2026

A token repeated across several posts is one advertising contract placed more than once, which is what the identifier is for. The strings are reproduced exactly as they appeared in the post or in its click-through URL and are not validated against any registry — we record the marker a channel published, and whether it resolves to a real contract is a question for the register that issued it.

Measured over the 27 most recent posts we hold, published 12 May 2026 to 2 September 2026. Views are the latest single reading held for each post, and any reading at or above 1,000 is rounded by Telegram to three significant figures.

Recent posts

2 Sept 2026, 09:55 UTC478 views5 reactionsread 2 September 2026

🔥 Java: subList() может неожиданно удерживать огромный список в памяти Кажется, что: List<Item> small = hugeList.subList(0, 10); hugeList = null; оставит только 10 элементов. Но subList() обычно создаёт представление исходного списка, а не независимую копию. Пока жив small, исходный ArrayList и его внутренний массив тоже могут оставаться в памяти. Если нужна отдельная маленькая коллекция: List<Item> small = …

🤔3❤1👍1

26 Aug 2026, 08:00 UTC≈1,400 views2 reactionsread 2 September 2026
Advertisementerid 2VtzqvimBRfPhoto

Приглашаем на курс для прокачки навыков архитектора и проектировщика, которые важны для профессионального роста программиста. 🌐 С курсом «Системный дизайн высоконагруженных проектов» вы: ▪️изучите ключевые фундаментальные паттерны и получите навыки проектирования проектов с миллионной аудиторией (балансировка, масштабирование апп/кешей/субд, высокая доступность и кластерные решения, шардинг, CAP/PACELS, консистентн…

❤1👍1

25 Aug 2026, 11:18 UTC≈1,310 views2 reactionsread 2 September 2026

Java-ловушка: почему `parallelStream()` может замедлить приложение Многие думают: «Есть stream(), добавлю parallelStream() — станет быстрее». Но не всегда. parallelStream() использует общий ForkJoinPool Java: users.parallelStream() .map(this::callExternalApi) .toList(); Если внутри идут HTTP-запросы, SQL или ожидание внешнего сервиса, можно получить обратный эффект: забить общий пул потоков увеличи…

❤1👍1

22 Aug 2026, 14:16 UTC≈1,350 viewsread 2 September 2026
Advertisementerid 2VtzqvSBEDRPhoto

Вам доклады по Go или Java? VK приглашает на митап с двойной начинкой 26 августа VK собирает Go- и Java-инженеров, чтобы прокачать знания. В программе два трека — Go и Java, по три доклада в каждом. Трек Go: • «Компиляция Go в динамическую либу, или как мы ускорили выкатку фичи в два раза, но нам не понравилось», Михаил Кичигин, бэкенд-разработчик, Avito Tech • «Go-платформа VK: как мы построили единую основу для с…

18 Aug 2026, 11:53 UTC≈1,800 views9 reactionsread 2 September 2026

Полезный Java-совет: Не вызывай parallelStream() просто потому, что данных много. Для коротких операций он легко оказывается медленнее обычного stream(), потому что платишь за разбиение задачи, синхронизацию и работу ForkJoinPool. Особенно неприятно то, что по умолчанию parallelStream() использует общий ForkJoinPool.commonPool(). Если приложение уже нагружает его другими задачами, производительность может внезапно…

❤5👍4

12 Aug 2026, 15:10 UTC≈2,340 views5 reactionsread 2 September 2026

⚡️ Java-приём: не храни метаданные классов в `static Map<Class<?>, ...>` — используй `ClassValue`. Допустим, библиотека кеширует информацию о каждом классе: private static final Map<Class<?>, Metadata> CACHE = new ConcurrentHashMap<>(); На первый взгляд всё нормально. Но в приложениях с динамической загрузкой классов — plugins, application servers, hot reload — такой кеш может удерживать Class, а вмест…

❤3👍2

6 Aug 2026, 21:11 UTC≈2,090 views11 reactionsread 2 September 2026

☕️ Java-совет: не запускайте блокирующий I/O через `CompletableFuture` без собственного пула Такой код выглядит асинхронным: CompletableFuture<User> future = CompletableFuture.supplyAsync(() -> userClient.loadUser(id)); Но без явного Executor задача обычно попадёт в общий ForkJoinPool.commonPool(). Если loadUser() ждёт HTTP, базу данных или файловую систему, поток блокируется. Несколько медленных вызов…

❤5👍4🔥2

6 Aug 2026, 10:20 UTC≈1,610 views5 reactionsread 2 September 2026
Photo

💡 Java совет: два пути могут указывать на один и тот же файл Path.equals() сравнивает только представление пути: Path a = Path.of("data.txt"); Path b = Path.of("./data.txt"); System.out.println(a.equals(b)); // false Хотя оба пути могут вести к одному файлу. Для проверки используйте: boolean same = Files.isSameFile(a, b); Files.isSameFile() обращается к файловой системе и учитывает: - относительные пути; …

❤3👍2

6 Aug 2026, 08:15 UTC≈1,240 views4 reactionsread 31 August 2026
Photo

Собираем бэкенд-комьюнити на JVM Day Бэкендеры, 29 августа в Москве пройдет хардкорная конференция. Ждут своих: Java-, Scala- и Kotlin-разработчиков, архитекторов и тимлидов. Здесь выступят и расскажут: — Андрей Кулешов — что нового в мире JVM за год. — Сергей Петрелевич — разработка по Mechanical Sympathy. — Александр Ланцов — Java после Loom: другие модели concurrency. — Антон Курако — как бенчмарки вводят в забл…

❤4

5 Aug 2026, 21:41 UTC≈1,270 views4 reactionsread 2 September 2026

💡 Java cj: unmodifiableList() не делает настоящую копию Эти два варианта выглядят похоже, но работают по-разному: List<String> source = new ArrayList<>(); source.add("Java"); List<String> view = Collections.unmodifiableList(source); List<String> copy = List.copyOf(source); source.add("Spring"); System.out.println(view); // [Java, Spring] System.out.println(copy); // [Java] Collections.unmodifiableList() созд…

👍3👏1

5 Aug 2026, 13:08 UTC≈1,180 views2 reactionsread 2 September 2026
Photo

🖥 Java можно учить месяцами - и всё равно бояться написать собственный сервер Курс «Java: с нуля до сетевого гуру» построен так, чтобы ты как можно быстрее перешёл от теории к рабочему коду. Сначала разберёшь основы языка, ООП, коллекции и исключения. Затем перейдёшь к тому, ради чего многие и выбирают Java: - многопоточность; - TCP/IP и сокеты; - клиент-серверные приложения; - обработка нескольких подключений; -…

❤2

4 Aug 2026, 14:55 UTC≈1,260 views7 reactionsread 2 September 2026

💡 Редкий совет Java: используйте `ClassValue` для кэша, привязанного к классу Обычно метаданные кэшируют так: Map<Class<?>, Metadata> cache = new ConcurrentHashMap<>(); Но такой кэш способен удерживать классы и их ClassLoader, создавая утечки памяти в плагинах, серверах приложений и системах с динамической загрузкой. Для подобных случаев в Java есть ClassValue: private static final ClassValue<Metadata> C…

👍4🔥2🥰1

Showing the 12 most recent of 27 posts we hold for @java_library. 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.

Polls

The poll we hold for this entry, as Telegram rendered it when we read the post. A poll’s figures keep moving after that, so each one is dated.

19 Jul 2026, 13:16 UTCAnonymous Quiz217 voters

❓Что из вариантов лучше всего описывается определением: Операция, которая содержит серию задач, которые должны быть выполнены либо все, либо не выполнена ни одна.

  1. Query6%
  2. Transaction88%
  3. Prepared statement4%
  4. Callback2%

Shares as published. No per-option vote count is published by Telegram, so none is shown.

Percentages only — there are no per-option vote counts here, because Telegram publishes none. The public post preview gives each option’s share and a single voter total, and nothing else. Multiplying one by the other would produce a per-option tally that looks measured and is not: the shares are rounded to whole numbers before we ever see them. We print what was published and leave the column that does not exist empty.

The shares need not add up to 100. Rounding alone puts many polls at 99 or 101. A poll that allows more than one answer per voter runs well past 100 by design, and several here do. The bars are drawn against a fixed 100% track at each option’s own percentage rather than normalised to the total, so a poll that exceeds it shows that it does instead of being quietly rescaled.

Read from the 27 most recent posts we hold, published 12 May 2026 to 2 September 2026. Telegram labels each poll by kind — an anonymous poll, a quiz, a closed set of final results — and that label is reproduced rather than paraphrased.

Forward network

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 29 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. The 24 listed below are the most frequent namers; the rest are counted above but not each listed.

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.

Senior Java Developer
@seniorjavist · 20,641
Telegram ranks this channel #17 of 89 here — alongside 88 others — read 26 September 2026
Java библиотека
@javalib · 30,666
Telegram ranks this channel #17 of 84 here — alongside 83 others — read 7 September 2026
Data Science
@datascienceiot · 42,634
Telegram ranks this channel #20 of 76 here — alongside 75 others — read 29 August 2026
Библиотека джависта | Java, Spring, Maven, Hibernate
@javaproglib · 22,022
Telegram ranks this channel #22 of 88 here — alongside 87 others — read 21 September 2026
Python вопросы с собеседований
@python_job_interview · 24,881
Telegram ranks this channel #39 of 90 here — alongside 89 others — read 15 September 2026
Linux Academy
@linuxacademiya · 28,434
Telegram ranks this channel #41 of 84 here — alongside 83 others — read 9 September 2026
hahacker_news
@hahacker_news · 25,571
Telegram ranks this channel #44 of 59 here — alongside 58 others — read 14 September 2026
Software Engineers ❤️🙃
@softwaredevelopers007 · 21,394
Telegram ranks this channel #49 of 60 here — alongside 59 others — read 23 September 2026
Data Science. SQL hub
@sqlhub · 35,960
Telegram ranks this channel #51 of 87 here — alongside 86 others — read 2 September 2026
Python/ django
@pythonl · 58,866
Telegram ranks this channel #61 of 84 here — alongside 83 others — read 22 August 2026

This channel appears in 10 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 27 September 2026 — this entry's latest reading, not the date you are reading this.

“Java Books” (@java_library), 14,224 subscribers as measured 27 September 2026. Telegram Register, tgregister.com/channel/java_library.

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.