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<title>Как эффективно работать со стримами | Java: Стримы</title>
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Как будто между ними пропустили \"и\" или запятую, или не определились с более подходящим словом и оставили оба))","plain_title":"Читаемость лучше важнее производительности Второй раз возвращаюсь к этом уроку и каждый раз глаз цепляется к этой фразе, так и задумано? Как будто между ними пропустили \"и\" или запятую, или не определились с более подходящим словом и оставили оба)) ","creator":{"public_name":"Purplehead","id":393483,"is_tutor":false},"comments":[{"creator":{"public_name":"Maksim Litvinov","id":198906,"is_tutor":true},"id":186124,"body":"Выбрал подходящее слово. Спасибо!","topic_id":95444}],"communitable":{"parent_entity_name":null,"parent_entity_url":null,"entity_name":"Как эффективно работать со стримами","entity_url":null,"active":true}},{"id":103340,"title":"> После терминальной операции стрим нельзя использовать повторно. Пример: После использования collect, исходный стрим больше не доступен:\n\nа о каком collect здесь идет речь?","plain_title":"После терминальной операции стрим нельзя использовать повторно. Пример: После использования collect, исходный стрим больше не доступен: а о каком collect здесь идет речь? ","creator":{"public_name":"Alex Smith","id":286685,"is_tutor":false},"comments":[{"creator":{"public_name":"Maksim Litvinov","id":198906,"is_tutor":true},"id":195712,"body":"Речь о методе свертки стрима `collect()`. Вот в этом [уроке](https://ru.hexlet.io/courses/java-streams/lessons/collectors/theory_unit) обсуждали различные методы свертки","topic_id":103340}],"communitable":{"parent_entity_name":null,"parent_entity_url":null,"entity_name":"Как эффективно работать со стримами","entity_url":null,"active":true}}],"lesson":{"exercise":{"id":2856,"slug":"java_streams_stream_rules_exercise","name":null,"state":"active","kind":"exercise","language":"java","locale":"ru","has_web_view":false,"has_test_view":false,"reviewable":true,"readme":"Вам наверняка часто попадались примеры, демонстрирующие работу стримов, где нужно найти максимальный или минимальный элемент в списке. В этом упражнении мы сделаем задачу чуть более интересной и найдем второй по величине элемент списка\n\n## src/main/java/io/hexlet/App.java\n\nВ классе `App` реализуйте публичный статический метод `getSecondBiggest()`, который принимает в качестве параметра список целых чисел `List<Integer>`. Метод должен вернуть второе по величине число из списка. Если найти такое число не представляется возможным (например, список пуст или в нем только один элемент), метод должен вернуть `null`\n\n\n```java\nvar numbers = List.of(3, -5, 6, 1, 0, -2, 10);\n\nApp.getSecondBiggest(numbers); // 6\n```\n","prepared_readme":"Вам наверняка часто попадались примеры, демонстрирующие работу стримов, где нужно найти максимальный или минимальный элемент в списке. В этом упражнении мы сделаем задачу чуть более интересной и найдем второй по величине элемент списка\n\n## src/main/java/io/hexlet/App.java\n\nВ классе `App` реализуйте публичный статический метод `getSecondBiggest()`, который принимает в качестве параметра список целых чисел `List<Integer>`. Метод должен вернуть второе по величине число из списка. Если найти такое число не представляется возможным (например, список пуст или в нем только один элемент), метод должен вернуть `null`\n\n\n```java\nvar numbers = List.of(3, -5, 6, 1, 0, -2, 10);\n\nApp.getSecondBiggest(numbers); // 6\n```\n","has_solution":true,"entity_name":"Как эффективно работать со стримами"},"units":[{"id":10582,"name":"theory","url":"/courses/java-streams/lessons/stream-rules/theory_unit"},{"id":10693,"name":"quiz","url":"/courses/java-streams/lessons/stream-rules/quiz_unit"},{"id":10684,"name":"exercise","url":"/courses/java-streams/lessons/stream-rules/exercise_unit"}],"links":[{"id":424980,"name":"Статья про Stream API","url":"https://habr.com/ru/articles/437038/\n"},{"id":424981,"name":"Дополнительная видео-лекциях о стримах","url":"https://vimeo.com/579150718/c71d7a93cf?share=copy&fl=sv&fe=ci\n"}],"ordered_units":[{"id":10582,"name":"theory","url":"/courses/java-streams/lessons/stream-rules/theory_unit"},{"id":10693,"name":"quiz","url":"/courses/java-streams/lessons/stream-rules/quiz_unit"},{"id":10684,"name":"exercise","url":"/courses/java-streams/lessons/stream-rules/exercise_unit"}],"id":4506,"slug":"stream-rules","state":"approved","name":"Как эффективно работать со стримами","course_order":850,"goal":"Изучить рекомендации по работе со стримами","self_study":null,"theory_video_provider":null,"theory_video_uid":null,"theory":"Как и любой мощный инструмент, стримы с одной стороны делают код короче и удобнее, но с другой, неправильное их использование может значительно все усложнить. Особенно учитывая то, что с помощью стримов одна и та же задача может быть решена совершенно разными способами. В этом уроке мы собрали рекомендации, которых важно придерживаться работая со стримами.\n\n## Приоритет читаемости и ясности\n\nСложные стримы разбивайте на более мелкие и понятные шаги. Пример: Если у вас есть список строк, и вы хотите отфильтровать те, которые начинаются на \"A\", а затем отсортировать их, лучше разделить эти шаги:\n\n```java\nvar strings = List.of(\"Apple\", \"Banana\", \"Avocado\");\nvar filteredSorted = strings.stream()\n .filter(s -> s.startsWith(\"A\"))\n .sorted()\n .toList();\n```\n\n## Избегайте побочных эффектов\n\nОперации со стримами должны избегать изменения исходных данных. Пример: Вместо изменения списка в `forEach()`, используйте map для создания нового списка:\n\n```java\nvar numbers = List.of(1, 2, 3);\nvar doubled = numbers.stream()\n .map(n -> n * 2)\n .toList();\n```\n\n## Читаемость важнее производительности\n\nИспользуйте стримы для улучшения читаемости кода. Пример: Использование стримов для фильтрации и преобразования коллекций:\n\n```java\nvar names = List.of(\"John\", \"Jane\", \"Adam\", \"Alice\");\nvar shortNames = names.stream()\n .filter(name -> name.length() <= 4)\n .toList();\n```\n\n## Используйте ссылки на методы\n\nДля упрощения кода используйте ссылки на методы. Пример: Преобразование строк в верхний регистр:\n\n```java\nvar names = List.of(\"John\", \"Jane\");\nvar upperCaseNames = names.stream()\n .map(String::toUpperCase)\n .toList();\n```\n\n## Ограничьте область применения потоков\n\nИспользуйте стримы для сложных операций с коллекциями. Пример: Неправильно использовать стримы для простой итерации:\n\n```java\n// Неэффективное использование потоков\nvar numbers = List.of(1, 2, 3);\nnumbers.stream().forEach(System.out::println);\n\n// Достаточно forEach() у списка\nnumbers.forEach(System.out::println);\n```\n\n## Будьте осторожны с терминальными операциями\n\nПосле терминальной операции стрим нельзя использовать повторно. Пример: После использования collect, исходный стрим больше не доступен:\n\n```java\nvar stream = Stream.of(\"a\", \"b\", \"c\");\nvar list = stream.toList();\n// stream уже не может быть использован здесь для других операций\n```\n\n## Используйте невмешательные операции\n\nНе изменяйте источник стрима во время его обработки. Пример: Изменение списка во время обработки стрима может привести к непредсказуемым результатам\n"},"lessonMember":null,"courseMember":null,"course":{"start_lesson":{"exercise":null,"units":[{"id":10573,"name":"theory","url":"/courses/java-streams/lessons/intro/theory_unit"}],"links":[],"ordered_units":[{"id":10573,"name":"theory","url":"/courses/java-streams/lessons/intro/theory_unit"}],"id":4497,"slug":"intro","state":"approved","name":"Введение","course_order":100,"goal":"Познакомиться с курсом","self_study":null,"theory_video_provider":null,"theory_video_uid":null,"theory":"Стримы Java - это абстракция, которая позволяет обрабатывать последовательности данных, например, коллекции в декларативном стиле. Мы начнем с основ, изучая, как стримы работают и как они могут упростить и улучшить ваш код.\n\nОсновные темы, которые мы рассмотрим:\n\n- Введение в стримы Java: Понимание основных концепций и принципов работы стримов.\n- Создание стримов: Изучение различных способов создания стримов из коллекций, массивов и других источников.\n- Операции со стримами: Освоение промежуточных и терминальных операций, таких как фильтрация, сортировка, преобразование и сбор результатов.\n- Понимание лямбда-выражений и функциональных интерфейсов: Ключевая часть для работы со стримами, позволяющая писать более компактный и читаемый код.\n- Лучшие практики и распространенные ошибки: Научитесь избегать типичных ошибок и следовать лучшим практикам при работе со стримами.\n"},"id":385,"slug":"java-streams","challenges_count":11,"name":"Java: Стримы","allow_indexing":true,"state":"approved","course_state":"finished","pricing_type":"paid","description":"На этом курсе вы узнаете, что такое стримы и как они могут быть использованы для обработки данных. Вы изучите основные методы, доступные в классе Stream и научитесь применять их для фильтрации, сортировки, маппинга и агрегации данных. Так же вы узнаете как эффективно использовать стримы для работы с данными и как оптимизировать производительность своих приложений.","kind":"additional","updated_at":"2026-01-20T11:51:06.468Z","language":"java","duration_cache":43260,"skills":["Понимать основные концепции и принципы работы стримов","Создавать стримы и производить с ними операции","Избегать типичных ошибок и следовать лучшим практикам при работе со 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0.15);--mantine-color-grape-light-hover: rgba(229, 153, 247, 0.2);--mantine-color-grape-light-color: var(--mantine-color-grape-0);--mantine-color-grape-outline: var(--mantine-color-grape-1);--mantine-color-grape-outline-hover: rgba(243, 217, 250, 0.05);--mantine-color-violet-filled: var(--mantine-color-violet-5);--mantine-color-violet-filled-hover: var(--mantine-color-violet-6);--mantine-color-violet-light: rgba(209, 111, 255, 0.15);--mantine-color-violet-light-hover: rgba(209, 111, 255, 0.2);--mantine-color-violet-light-color: var(--mantine-color-violet-0);--mantine-color-violet-outline: var(--mantine-color-violet-1);--mantine-color-violet-outline-hover: rgba(241, 207, 255, 0.05);--mantine-color-indigo-filled: var(--mantine-color-indigo-5);--mantine-color-indigo-filled-hover: var(--mantine-color-indigo-6);--mantine-color-indigo-light: rgba(123, 121, 235, 0.15);--mantine-color-indigo-light-hover: rgba(123, 121, 235, 0.2);--mantine-color-indigo-light-color: var(--mantine-color-indigo-0);--mantine-color-indigo-outline: var(--mantine-color-indigo-1);--mantine-color-indigo-outline-hover: rgba(214, 213, 254, 0.05);--mantine-color-blue-filled: var(--mantine-color-blue-5);--mantine-color-blue-filled-hover: var(--mantine-color-blue-6);--mantine-color-blue-light: rgba(116, 192, 252, 0.15);--mantine-color-blue-light-hover: rgba(116, 192, 252, 0.2);--mantine-color-blue-light-color: var(--mantine-color-blue-0);--mantine-color-blue-outline: var(--mantine-color-blue-1);--mantine-color-blue-outline-hover: rgba(208, 235, 255, 0.05);--mantine-color-cyan-filled: var(--mantine-color-cyan-5);--mantine-color-cyan-filled-hover: var(--mantine-color-cyan-6);--mantine-color-cyan-light: rgba(100, 218, 255, 0.15);--mantine-color-cyan-light-hover: rgba(100, 218, 255, 0.2);--mantine-color-cyan-light-color: var(--mantine-color-cyan-0);--mantine-color-cyan-outline: var(--mantine-color-cyan-1);--mantine-color-cyan-outline-hover: rgba(202, 245, 255, 0.05);--mantine-color-teal-filled: var(--mantine-color-teal-5);--mantine-color-teal-filled-hover: var(--mantine-color-teal-6);--mantine-color-teal-light: rgba(99, 230, 190, 0.15);--mantine-color-teal-light-hover: rgba(99, 230, 190, 0.2);--mantine-color-teal-light-color: var(--mantine-color-teal-0);--mantine-color-teal-outline: var(--mantine-color-teal-1);--mantine-color-teal-outline-hover: rgba(195, 250, 232, 0.05);--mantine-color-green-filled: var(--mantine-color-green-5);--mantine-color-green-filled-hover: var(--mantine-color-green-6);--mantine-color-green-light: rgba(134, 223, 148, 0.15);--mantine-color-green-light-hover: rgba(134, 223, 148, 0.2);--mantine-color-green-light-color: var(--mantine-color-green-0);--mantine-color-green-outline: var(--mantine-color-green-1);--mantine-color-green-outline-hover: rgba(215, 246, 220, 0.05);--mantine-color-lime-filled: var(--mantine-color-lime-5);--mantine-color-lime-filled-hover: var(--mantine-color-lime-6);--mantine-color-lime-light: rgba(192, 235, 117, 0.15);--mantine-color-lime-light-hover: rgba(192, 235, 117, 0.2);--mantine-color-lime-light-color: var(--mantine-color-lime-0);--mantine-color-lime-outline: var(--mantine-color-lime-1);--mantine-color-lime-outline-hover: rgba(233, 250, 200, 0.05);--mantine-color-yellow-filled: var(--mantine-color-yellow-5);--mantine-color-yellow-filled-hover: var(--mantine-color-yellow-6);--mantine-color-yellow-light: rgba(255, 201, 102, 0.15);--mantine-color-yellow-light-hover: rgba(255, 201, 102, 0.2);--mantine-color-yellow-light-color: var(--mantine-color-yellow-0);--mantine-color-yellow-outline: var(--mantine-color-yellow-1);--mantine-color-yellow-outline-hover: rgba(255, 238, 205, 0.05);--mantine-color-orange-filled: var(--mantine-color-orange-5);--mantine-color-orange-filled-hover: var(--mantine-color-orange-6);--mantine-color-orange-light: rgba(255, 192, 120, 0.15);--mantine-color-orange-light-hover: rgba(255, 192, 120, 0.2);--mantine-color-orange-light-color: var(--mantine-color-orange-0);--mantine-color-orange-outline: var(--mantine-color-orange-1);--mantine-color-orange-outline-hover: rgba(255, 232, 204, 0.05);--app-cta-gradient: linear-gradient(90deg, var(--mantine-color-blue-9) 0%, var(--mantine-color-cyan-7) 100%);--app-color-surface: #2e2e2e;}
:root[data-mantine-color-scheme="light"], :host([data-mantine-color-scheme="light"]){--mantine-color-anchor: var(--mantine-color-text);--mantine-color-dimmed: #495057;--mantine-color-red-light: rgba(224, 40, 41, 0.1);--mantine-color-red-light-hover: rgba(224, 40, 41, 0.12);--mantine-color-red-outline-hover: rgba(224, 40, 41, 0.05);--mantine-color-violet-light: rgba(176, 9, 255, 0.1);--mantine-color-violet-light-hover: rgba(176, 9, 255, 0.12);--mantine-color-violet-outline-hover: rgba(176, 9, 255, 0.05);--mantine-color-indigo-light: rgba(45, 42, 223, 0.1);--mantine-color-indigo-light-hover: rgba(45, 42, 223, 0.12);--mantine-color-indigo-outline-hover: rgba(45, 42, 223, 0.05);--mantine-color-cyan-light: rgba(0, 194, 255, 0.1);--mantine-color-cyan-light-hover: rgba(0, 194, 255, 0.12);--mantine-color-cyan-outline-hover: rgba(0, 194, 255, 0.05);--mantine-color-green-light: rgba(63, 204, 84, 0.1);--mantine-color-green-light-hover: rgba(63, 204, 84, 0.12);--mantine-color-green-outline-hover: rgba(63, 204, 84, 0.05);--mantine-color-yellow-light: rgba(255, 169, 15, 0.1);--mantine-color-yellow-light-hover: rgba(255, 169, 15, 0.12);--mantine-color-yellow-outline-hover: rgba(255, 169, 15, 0.05);--app-color-surface: #f1f3f5;--app-cta-gradient: linear-gradient(90deg, var(--mantine-color-blue-filled) 0%, var(--mantine-color-cyan-5) 100%);}</style><style data-mantine-styles="classes">@media (max-width: 35.99375em) {.mantine-visible-from-xs {display: none !important;}}@media (min-width: 36em) {.mantine-hidden-from-xs {display: none !important;}}@media (max-width: 47.99375em) {.mantine-visible-from-sm {display: none !important;}}@media (min-width: 48em) {.mantine-hidden-from-sm {display: none !important;}}@media (max-width: 61.99375em) {.mantine-visible-from-md {display: none !important;}}@media (min-width: 62em) {.mantine-hidden-from-md {display: none !important;}}@media (max-width: 74.99375em) {.mantine-visible-from-lg {display: none !important;}}@media (min-width: 75em) {.mantine-hidden-from-lg {display: none !important;}}@media (max-width: 87.99375em) {.mantine-visible-from-xl {display: none !important;}}@media (min-width: 88em) {.mantine-hidden-from-xl {display: none !important;}}</style><div style="position:absolute;top:0rem" class=""></div><div style="max-width:var(--container-size-xl);height:100%;min-height:0rem" class=""><style data-mantine-styles="inline">.__m__-_R_5ub_{--grid-gutter:0rem;}</style><div style="height:100%;min-height:0rem" class="m_410352e9 mantine-Grid-root __m__-_R_5ub_"><div class="m_dee7bd2f mantine-Grid-inner" style="height:100%"><style data-mantine-styles="inline">.__m__-_R_rdub_{--col-flex-grow:auto;--col-flex-basis:91.66666666666667%;--col-max-width:91.66666666666667%;}@media(min-width: 48em){.__m__-_R_rdub_{--col-flex-grow:auto;--col-flex-basis:83.33333333333334%;--col-max-width:83.33333333333334%;}}</style><div style="min-width:0rem;height:100%;min-height:0rem;display:flex" class="m_96bdd299 mantine-Grid-col __m__-_R_rdub_"><style data-mantine-styles="inline">.__m__-_R_6qrdub_{margin-top:0rem;padding-inline:var(--mantine-spacing-xs);width:100%;}@media(min-width: 48em){.__m__-_R_6qrdub_{margin-top:var(--mantine-spacing-xl);width:80%;}}@media(min-width: 62em){.__m__-_R_6qrdub_{padding-inline:var(--mantine-spacing-xl);}}</style><div style="margin-inline:auto;max-width:var(--mantine-breakpoint-xl)" class="__m__-_R_6qrdub_"><div style="color:var(--mantine-color-dimmed)" class="m_4451eb3a mantine-Center-root" data-inline="true"><div style="--ti-size:var(--ti-size-xs);--ti-bg:transparent;--ti-color:var(--mantine-color-indigo-light-color);--ti-bd:calc(0.0625rem * var(--mantine-scale)) solid transparent;margin-inline-end:calc(0.125rem * var(--mantine-scale));color:inherit" class="m_7341320d mantine-ThemeIcon-root" data-variant="transparent" data-size="xs"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="tabler-icon tabler-icon-lock "><path d="M5 13a2 2 0 0 1 2 -2h10a2 2 0 0 1 2 2v6a2 2 0 0 1 -2 2h-10a2 2 0 0 1 -2 -2v-6"></path><path d="M11 16a1 1 0 1 0 2 0a1 1 0 0 0 -2 0"></path><path d="M8 11v-4a4 4 0 1 1 8 0v4"></path></svg></div><p style="font-size:var(--mantine-font-size-sm)" class="mantine-focus-auto m_b6d8b162 mantine-Text-root">Java: Стримы</p></div><h1 style="--title-fw:var(--mantine-h1-font-weight);--title-lh:var(--mantine-h1-line-height);--title-fz:var(--mantine-h1-font-size);margin-bottom:var(--mantine-spacing-xl)" class="m_8a5d1357 mantine-Title-root" data-order="1">Теория: Как эффективно работать со стримами</h1><script type="application/ld+json">{"@context":"https://schema.org","@type":"LearningResource","name":"Как эффективно работать со стримами","inLanguage":"ru","isPartOf":{"@type":"LearningResource","name":"Java: Стримы"},"isAccessibleForFree":"False","hasPart":{"@type":"WebPageElement","isAccessibleForFree":"False","cssSelector":".paywalled"}}</script><div class=""><div style="--alert-color:var(--mantine-color-indigo-light-color);margin-bottom:var(--mantine-spacing-lg);font-size:var(--mantine-font-size-lg)" class="m_66836ed3 mantine-Alert-root" id="mantine-_R_remqrdub_" role="alert" aria-describedby="mantine-_R_remqrdub_-body" aria-labelledby="mantine-_R_remqrdub_-title"><div class="m_a5d60502 mantine-Alert-wrapper"><div class="m_667f2a6a mantine-Alert-icon"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="tabler-icon tabler-icon-rocket "><path d="M4 13a8 8 0 0 1 7 7a6 6 0 0 0 3 -5a9 9 0 0 0 6 -8a3 3 0 0 0 -3 -3a9 9 0 0 0 -8 6a6 6 0 0 0 -5 3"></path><path d="M7 14a6 6 0 0 0 -3 6a6 6 0 0 0 6 -3"></path><path d="M14 9a1 1 0 1 0 2 0a1 1 0 1 0 -2 0"></path></svg></div><div class="m_667c2793 mantine-Alert-body"><div class="m_6a03f287 mantine-Alert-title"><span id="mantine-_R_remqrdub_-title" class="m_698f4f23 mantine-Alert-label">Полный доступ к материалам</span></div><div id="mantine-_R_remqrdub_-body" class="m_7fa78076 mantine-Alert-message"><div style="--group-gap:var(--mantine-spacing-md);--group-align:center;--group-justify:space-between;--group-wrap:wrap" class="m_4081bf90 mantine-Group-root"><p class="mantine-focus-auto m_b6d8b162 mantine-Text-root">Зарегистрируйтесь и получите доступ к этому и десяткам других курсов</p><a style="--button-height:var(--button-height-xs);--button-padding-x:var(--button-padding-x-xs);--button-fz:var(--mantine-font-size-xs);--button-bg:linear-gradient(45deg, var(--mantine-color-blue-filled) 0%, var(--mantine-color-cyan-filled) 100%);--button-hover:linear-gradient(45deg, var(--mantine-color-blue-filled) 0%, var(--mantine-color-cyan-filled) 100%);--button-color:var(--mantine-color-white);--button-bd:none" class="mantine-focus-auto mantine-active m_77c9d27d mantine-Button-root m_87cf2631 mantine-UnstyledButton-root" data-variant="gradient" data-size="xs" href="/u/new"><span class="m_80f1301b mantine-Button-inner"><span class="m_811560b9 mantine-Button-label">Зарегистрироваться</span></span></a></div></div></div></div></div><div class="paywalled m_d08caa0 mantine-Typography-root"><p>Как и любой мощный инструмент, стримы с одной стороны делают код короче и удобнее, но с другой, неправильное их использование может значительно все усложнить. Особенно учитывая то, что с помощью стримов одна и та же задача может быть решена совершенно разными способами. В этом уроке мы собрали рекомендации, которых важно придерживаться работая со стримами.</p>
<h2 id="heading-2-1">Приоритет читаемости и ясности</h2>
<p>Сложные стримы разбивайте на более мелкие и понятные шаги. Пример: Если у вас есть список строк, и вы хотите отфильтровать те, которые начинаются на "A", а затем отсортировать их, лучше разделить эти шаги:</p>
<div style="margin-bottom:var(--mantine-spacing-lg)" class="m_e597c321 mantine-CodeHighlight-codeHighlight" dir="ltr"><div class="m_be7e9c9c mantine-CodeHighlight-controls"><button style="--ai-bg:transparent;--ai-hover:transparent;--ai-color:inherit;--ai-bd:none" class="mantine-focus-auto mantine-active m_d498bab7 mantine-CodeHighlight-control m_8d3f4000 mantine-ActionIcon-root m_87cf2631 mantine-UnstyledButton-root" data-variant="none" type="button" aria-label="Copy code"><span class="m_8d3afb97 mantine-ActionIcon-icon"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M8 8m0 2a2 2 0 0 1 2 -2h8a2 2 0 0 1 2 2v8a2 2 0 0 1 -2 2h-8a2 2 0 0 1 -2 -2z"></path><path d="M16 8v-2a2 2 0 0 0 -2 -2h-8a2 2 0 0 0 -2 2v8a2 2 0 0 0 2 2h2"></path></svg></span></button></div><div style="--scrollarea-scrollbar-size:calc(0.25rem * var(--mantine-scale));--sa-corner-width:0px;--sa-corner-height:0px" class="m_f744fd40 mantine-CodeHighlight-scrollarea m_d57069b5 mantine-ScrollArea-root" dir="ltr"><div style="overflow-x:hidden;overflow-y:hidden;overscroll-behavior-inline:none" class="m_c0783ff9 mantine-ScrollArea-viewport" data-scrollbars="xy"><div class="m_b1336c6 mantine-ScrollArea-content"><pre class="m_2c47c4fd mantine-CodeHighlight-pre" style="padding:0"><code class="m_5caae6d3 mantine-CodeHighlight-code">var strings = List.of("Apple", "Banana", "Avocado");
var filteredSorted = strings.stream()
.filter(s -> s.startsWith("A"))
.sorted()
.toList();</code></pre></div></div></div><button class="mantine-focus-auto m_c9378bc2 mantine-CodeHighlight-showCodeButton m_87cf2631 mantine-UnstyledButton-root" data-hidden="true" type="button">Expand code</button></div>
<h2 id="heading-2-2">Избегайте побочных эффектов</h2>
<p>Операции со стримами должны избегать изменения исходных данных. Пример: Вместо изменения списка в <code style="margin-bottom:var(--mantine-spacing-lg)" class="m_dfe9c588 mantine-InlineCodeHighlight-inlineCodeHighlight m_e597c321 mantine-CodeHighlight-codeHighlight m_dfe9c588 mantine-InlineCodeHighlight-inlineCodeHighlight">forEach()</code>, используйте map для создания нового списка:</p>
<div style="margin-bottom:var(--mantine-spacing-lg)" class="m_e597c321 mantine-CodeHighlight-codeHighlight" dir="ltr"><div class="m_be7e9c9c mantine-CodeHighlight-controls"><button style="--ai-bg:transparent;--ai-hover:transparent;--ai-color:inherit;--ai-bd:none" class="mantine-focus-auto mantine-active m_d498bab7 mantine-CodeHighlight-control m_8d3f4000 mantine-ActionIcon-root m_87cf2631 mantine-UnstyledButton-root" data-variant="none" type="button" aria-label="Copy code"><span class="m_8d3afb97 mantine-ActionIcon-icon"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M8 8m0 2a2 2 0 0 1 2 -2h8a2 2 0 0 1 2 2v8a2 2 0 0 1 -2 2h-8a2 2 0 0 1 -2 -2z"></path><path d="M16 8v-2a2 2 0 0 0 -2 -2h-8a2 2 0 0 0 -2 2v8a2 2 0 0 0 2 2h2"></path></svg></span></button></div><div style="--scrollarea-scrollbar-size:calc(0.25rem * var(--mantine-scale));--sa-corner-width:0px;--sa-corner-height:0px" class="m_f744fd40 mantine-CodeHighlight-scrollarea m_d57069b5 mantine-ScrollArea-root" dir="ltr"><div style="overflow-x:hidden;overflow-y:hidden;overscroll-behavior-inline:none" class="m_c0783ff9 mantine-ScrollArea-viewport" data-scrollbars="xy"><div class="m_b1336c6 mantine-ScrollArea-content"><pre class="m_2c47c4fd mantine-CodeHighlight-pre" style="padding:0"><code class="m_5caae6d3 mantine-CodeHighlight-code">var numbers = List.of(1, 2, 3);
var doubled = numbers.stream()
.map(n -> n * 2)
.toList();</code></pre></div></div></div><button class="mantine-focus-auto m_c9378bc2 mantine-CodeHighlight-showCodeButton m_87cf2631 mantine-UnstyledButton-root" data-hidden="true" type="button">Expand code</button></div>
<h2 id="heading-2-3">Читаемость важнее производительности</h2>
<p>Используйте стримы для улучшения читаемости кода. Пример: Использование стримов для фильтрации и преобразования коллекций:</p>
<div style="margin-bottom:var(--mantine-spacing-lg)" class="m_e597c321 mantine-CodeHighlight-codeHighlight" dir="ltr"><div class="m_be7e9c9c mantine-CodeHighlight-controls"><button style="--ai-bg:transparent;--ai-hover:transparent;--ai-color:inherit;--ai-bd:none" class="mantine-focus-auto mantine-active m_d498bab7 mantine-CodeHighlight-control m_8d3f4000 mantine-ActionIcon-root m_87cf2631 mantine-UnstyledButton-root" data-variant="none" type="button" aria-label="Copy code"><span class="m_8d3afb97 mantine-ActionIcon-icon"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M8 8m0 2a2 2 0 0 1 2 -2h8a2 2 0 0 1 2 2v8a2 2 0 0 1 -2 2h-8a2 2 0 0 1 -2 -2z"></path><path d="M16 8v-2a2 2 0 0 0 -2 -2h-8a2 2 0 0 0 -2 2v8a2 2 0 0 0 2 2h2"></path></svg></span></button></div><div style="--scrollarea-scrollbar-size:calc(0.25rem * var(--mantine-scale));--sa-corner-width:0px;--sa-corner-height:0px" class="m_f744fd40 mantine-CodeHighlight-scrollarea m_d57069b5 mantine-ScrollArea-root" dir="ltr"><div style="overflow-x:hidden;overflow-y:hidden;overscroll-behavior-inline:none" class="m_c0783ff9 mantine-ScrollArea-viewport" data-scrollbars="xy"><div class="m_b1336c6 mantine-ScrollArea-content"><pre class="m_2c47c4fd mantine-CodeHighlight-pre" style="padding:0"><code class="m_5caae6d3 mantine-CodeHighlight-code">var names = List.of("John", "Jane", "Adam", "Alice");
var shortNames = names.stream()
.filter(name -> name.length() <= 4)
.toList();</code></pre></div></div></div><button class="mantine-focus-auto m_c9378bc2 mantine-CodeHighlight-showCodeButton m_87cf2631 mantine-UnstyledButton-root" data-hidden="true" type="button">Expand code</button></div>
<h2 id="heading-2-4">Используйте ссылки на методы</h2>
<p>Для упрощения кода используйте ссылки на методы. Пример: Преобразование строк в верхний регистр:</p>
<div style="margin-bottom:var(--mantine-spacing-lg)" class="m_e597c321 mantine-CodeHighlight-codeHighlight" dir="ltr"><div class="m_be7e9c9c mantine-CodeHighlight-controls"><button style="--ai-bg:transparent;--ai-hover:transparent;--ai-color:inherit;--ai-bd:none" class="mantine-focus-auto mantine-active m_d498bab7 mantine-CodeHighlight-control m_8d3f4000 mantine-ActionIcon-root m_87cf2631 mantine-UnstyledButton-root" data-variant="none" type="button" aria-label="Copy code"><span class="m_8d3afb97 mantine-ActionIcon-icon"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M8 8m0 2a2 2 0 0 1 2 -2h8a2 2 0 0 1 2 2v8a2 2 0 0 1 -2 2h-8a2 2 0 0 1 -2 -2z"></path><path d="M16 8v-2a2 2 0 0 0 -2 -2h-8a2 2 0 0 0 -2 2v8a2 2 0 0 0 2 2h2"></path></svg></span></button></div><div style="--scrollarea-scrollbar-size:calc(0.25rem * var(--mantine-scale));--sa-corner-width:0px;--sa-corner-height:0px" class="m_f744fd40 mantine-CodeHighlight-scrollarea m_d57069b5 mantine-ScrollArea-root" dir="ltr"><div style="overflow-x:hidden;overflow-y:hidden;overscroll-behavior-inline:none" class="m_c0783ff9 mantine-ScrollArea-viewport" data-scrollbars="xy"><div class="m_b1336c6 mantine-ScrollArea-content"><pre class="m_2c47c4fd mantine-CodeHighlight-pre" style="padding:0"><code class="m_5caae6d3 mantine-CodeHighlight-code">var names = List.of("John", "Jane");
var upperCaseNames = names.stream()
.map(String::toUpperCase)
.toList();</code></pre></div></div></div><button class="mantine-focus-auto m_c9378bc2 mantine-CodeHighlight-showCodeButton m_87cf2631 mantine-UnstyledButton-root" data-hidden="true" type="button">Expand code</button></div>
<h2 id="heading-2-5">Ограничьте область применения потоков</h2>
<p>Используйте стримы для сложных операций с коллекциями. Пример: Неправильно использовать стримы для простой итерации:</p>
<div style="margin-bottom:var(--mantine-spacing-lg)" class="m_e597c321 mantine-CodeHighlight-codeHighlight" dir="ltr"><div class="m_be7e9c9c mantine-CodeHighlight-controls"><button style="--ai-bg:transparent;--ai-hover:transparent;--ai-color:inherit;--ai-bd:none" class="mantine-focus-auto mantine-active m_d498bab7 mantine-CodeHighlight-control m_8d3f4000 mantine-ActionIcon-root m_87cf2631 mantine-UnstyledButton-root" data-variant="none" type="button" aria-label="Copy code"><span class="m_8d3afb97 mantine-ActionIcon-icon"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M8 8m0 2a2 2 0 0 1 2 -2h8a2 2 0 0 1 2 2v8a2 2 0 0 1 -2 2h-8a2 2 0 0 1 -2 -2z"></path><path d="M16 8v-2a2 2 0 0 0 -2 -2h-8a2 2 0 0 0 -2 2v8a2 2 0 0 0 2 2h2"></path></svg></span></button></div><div style="--scrollarea-scrollbar-size:calc(0.25rem * var(--mantine-scale));--sa-corner-width:0px;--sa-corner-height:0px" class="m_f744fd40 mantine-CodeHighlight-scrollarea m_d57069b5 mantine-ScrollArea-root" dir="ltr"><div style="overflow-x:hidden;overflow-y:hidden;overscroll-behavior-inline:none" class="m_c0783ff9 mantine-ScrollArea-viewport" data-scrollbars="xy"><div class="m_b1336c6 mantine-ScrollArea-content"><pre class="m_2c47c4fd mantine-CodeHighlight-pre" style="padding:0"><code class="m_5caae6d3 mantine-CodeHighlight-code">// Неэффективное использование потоков
var numbers = List.of(1, 2, 3);
numbers.stream().forEach(System.out::println);
// Достаточно forEach() у списка
numbers.forEach(System.out::println);</code></pre></div></div></div><button class="mantine-focus-auto m_c9378bc2 mantine-CodeHighlight-showCodeButton m_87cf2631 mantine-UnstyledButton-root" data-hidden="true" type="button">Expand code</button></div>
<h2 id="heading-2-6">Будьте осторожны с терминальными операциями</h2>
<p>После терминальной операции стрим нельзя использовать повторно. Пример: После использования collect, исходный стрим больше не доступен:</p>
<div style="margin-bottom:var(--mantine-spacing-lg)" class="m_e597c321 mantine-CodeHighlight-codeHighlight" dir="ltr"><div class="m_be7e9c9c mantine-CodeHighlight-controls"><button style="--ai-bg:transparent;--ai-hover:transparent;--ai-color:inherit;--ai-bd:none" class="mantine-focus-auto mantine-active m_d498bab7 mantine-CodeHighlight-control m_8d3f4000 mantine-ActionIcon-root m_87cf2631 mantine-UnstyledButton-root" data-variant="none" type="button" aria-label="Copy code"><span class="m_8d3afb97 mantine-ActionIcon-icon"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M8 8m0 2a2 2 0 0 1 2 -2h8a2 2 0 0 1 2 2v8a2 2 0 0 1 -2 2h-8a2 2 0 0 1 -2 -2z"></path><path d="M16 8v-2a2 2 0 0 0 -2 -2h-8a2 2 0 0 0 -2 2v8a2 2 0 0 0 2 2h2"></path></svg></span></button></div><div style="--scrollarea-scrollbar-size:calc(0.25rem * var(--mantine-scale));--sa-corner-width:0px;--sa-corner-height:0px" class="m_f744fd40 mantine-CodeHighlight-scrollarea m_d57069b5 mantine-ScrollArea-root" dir="ltr"><div style="overflow-x:hidden;overflow-y:hidden;overscroll-behavior-inline:none" class="m_c0783ff9 mantine-ScrollArea-viewport" data-scrollbars="xy"><div class="m_b1336c6 mantine-ScrollArea-content"><pre class="m_2c47c4fd mantine-CodeHighlight-pre" style="padding:0"><code class="m_5caae6d3 mantine-CodeHighlight-code">var stream = Stream.of("a", "b", "c");
var list = stream.toList();
// stream уже не может быть использован здесь для других операций</code></pre></div></div></div><button class="mantine-focus-auto m_c9378bc2 mantine-CodeHighlight-showCodeButton m_87cf2631 mantine-UnstyledButton-root" data-hidden="true" type="button">Expand code</button></div>
<h2 id="heading-2-7">Используйте невмешательные операции</h2>
<p>Не изменяйте источник стрима во время его обработки. Пример: Изменение списка во время обработки стрима может привести к непредсказуемым результатам</p></div><div style="margin-block:var(--mantine-spacing-xl)" class=""><h2 style="--title-fw:var(--mantine-h2-font-weight);--title-lh:var(--mantine-h2-line-height);--title-fz:var(--mantine-h2-font-size);margin-bottom:var(--mantine-spacing-md)" class="m_8a5d1357 mantine-Title-root" data-order="2">Рекомендуемые программы</h2><style data-mantine-styles="inline">.__m__-_R_2mremqrdub_{--carousel-slide-gap:var(--mantine-spacing-xs);--carousel-slide-size:70%;}@media(min-width: 36em){.__m__-_R_2mremqrdub_{--carousel-slide-gap:var(--mantine-spacing-xl);--carousel-slide-size:50%;}}</style><div style="--carousel-control-size:calc(2.5rem * var(--mantine-scale));--carousel-controls-offset:var(--mantine-spacing-sm);margin-bottom:var(--mantine-spacing-lg);padding-block:var(--mantine-spacing-sm);background:var(--app-color-surface)" class="m_17884d0f mantine-Carousel-root responsiveClassName" 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