Google Git
Sign in
fuchsia / third_party / github.com / google / flatbuffers / refs/heads/upstream/gh-pages / . / languages / java / index.html
blob: 219847700b5a8b6671e55eef46457a6d21421575 [file] [log] [blame] [edit]
<!doctype html>
<html lang="en" class="no-js">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<link rel="canonical" href="https://flatbuffers.dev/languages/java/">
<link rel="prev" href="../go/">
<link rel="next" href="../javascript/">
<link rel="icon" href="../../assets/images/favicon.png">
<meta name="generator" content="mkdocs-1.6.1, mkdocs-material-9.6.16">
<title>Java - FlatBuffers Docs</title>
<link rel="stylesheet" href="../../assets/stylesheets/main.7e37652d.min.css">
<link rel="stylesheet" href="../../assets/stylesheets/palette.06af60db.min.css">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Roboto:300,300i,400,400i,700,700i%7CRoboto+Mono:400,400i,700,700i&display=fallback">
<style>:root{--md-text-font:"Roboto";--md-code-font:"Roboto Mono"}</style>
<script>__md_scope=new URL("../..",location),__md_hash=e=>[...e].reduce(((e,_)=>(e<<5)-e+_.charCodeAt(0)),0),__md_get=(e,_=localStorage,t=__md_scope)=>JSON.parse(_.getItem(t.pathname+"."+e)),__md_set=(e,_,t=localStorage,a=__md_scope)=>{try{t.setItem(a.pathname+"."+e,JSON.stringify(_))}catch(e){}}</script>
</head>
<body dir="ltr" data-md-color-scheme="default" data-md-color-primary="indigo" data-md-color-accent="indigo">
<input class="md-toggle" data-md-toggle="drawer" type="checkbox" id="__drawer" autocomplete="off">
<input class="md-toggle" data-md-toggle="search" type="checkbox" id="__search" autocomplete="off">
<label class="md-overlay" for="__drawer"></label>
<div data-md-component="skip">
<a href="#flatbuffers_guide_use_java" class="md-skip">
Skip to content
</a>
</div>
<div data-md-component="announce">
</div>
<header class="md-header md-header--shadow" data-md-component="header">
<nav class="md-header__inner md-grid" aria-label="Header">
<a href="../.." title="FlatBuffers Docs" class="md-header__button md-logo" aria-label="FlatBuffers Docs" data-md-component="logo">
<img src="../../assets/flatbuffers_logo.svg" alt="logo">
</a>
<label class="md-header__button md-icon" for="__drawer">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M3 6h18v2H3zm0 5h18v2H3zm0 5h18v2H3z"/></svg>
</label>
<div class="md-header__title" data-md-component="header-title">
<div class="md-header__ellipsis">
<div class="md-header__topic">
<span class="md-ellipsis">
FlatBuffers Docs
</span>
</div>
<div class="md-header__topic" data-md-component="header-topic">
<span class="md-ellipsis">
Java
</span>
</div>
</div>
</div>
<form class="md-header__option" data-md-component="palette">
<input class="md-option" data-md-color-media="" data-md-color-scheme="default" data-md-color-primary="indigo" data-md-color-accent="indigo" aria-label="Switch to dark mode" type="radio" name="__palette" id="__palette_0">
<label class="md-header__button md-icon" title="Switch to dark mode" for="__palette_1" hidden>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M12 8a4 4 0 0 0-4 4 4 4 0 0 0 4 4 4 4 0 0 0 4-4 4 4 0 0 0-4-4m0 10a6 6 0 0 1-6-6 6 6 0 0 1 6-6 6 6 0 0 1 6 6 6 6 0 0 1-6 6m8-9.31V4h-4.69L12 .69 8.69 4H4v4.69L.69 12 4 15.31V20h4.69L12 23.31 15.31 20H20v-4.69L23.31 12z"/></svg>
</label>
<input class="md-option" data-md-color-media="" data-md-color-scheme="slate" data-md-color-primary="indigo" data-md-color-accent="indigo" aria-label="Switch to light mode" type="radio" name="__palette" id="__palette_1">
<label class="md-header__button md-icon" title="Switch to light mode" for="__palette_0" hidden>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M12 18c-.89 0-1.74-.2-2.5-.55C11.56 16.5 13 14.42 13 12s-1.44-4.5-3.5-5.45C10.26 6.2 11.11 6 12 6a6 6 0 0 1 6 6 6 6 0 0 1-6 6m8-9.31V4h-4.69L12 .69 8.69 4H4v4.69L.69 12 4 15.31V20h4.69L12 23.31 15.31 20H20v-4.69L23.31 12z"/></svg>
</label>
</form>
<script>var palette=__md_get("__palette");if(palette&&palette.color){if("(prefers-color-scheme)"===palette.color.media){var media=matchMedia("(prefers-color-scheme: light)"),input=document.querySelector(media.matches?"[data-md-color-media='(prefers-color-scheme: light)']":"[data-md-color-media='(prefers-color-scheme: dark)']");palette.color.media=input.getAttribute("data-md-color-media"),palette.color.scheme=input.getAttribute("data-md-color-scheme"),palette.color.primary=input.getAttribute("data-md-color-primary"),palette.color.accent=input.getAttribute("data-md-color-accent")}for(var[key,value]of Object.entries(palette.color))document.body.setAttribute("data-md-color-"+key,value)}</script>
<div class="md-header__source">
<a href="https://github.com/google/flatbuffers" title="Go to repository" class="md-source" data-md-component="source">
<div class="md-source__icon md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!--! Font Awesome Free 7.0.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path fill="currentColor" d="M173.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6m-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3m44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9M252.8 8C114.1 8 8 113.3 8 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C436.2 457.8 504 362.9 504 252 504 113.3 391.5 8 252.8 8M105.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1m-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7m32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1m-11.4-14.7c-1.6 1-1.6 3.6 0 5.9s4.3 3.3 5.6 2.3c1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2"/></svg>
</div>
<div class="md-source__repository">
google/FlatBuffers
</div>
</a>
</div>
</nav>
</header>
<div class="md-container" data-md-component="container">
<main class="md-main" data-md-component="main">
<div class="md-main__inner md-grid">
<div class="md-sidebar md-sidebar--primary" data-md-component="sidebar" data-md-type="navigation" >
<div class="md-sidebar__scrollwrap">
<div class="md-sidebar__inner">
<nav class="md-nav md-nav--primary" aria-label="Navigation" data-md-level="0">
<label class="md-nav__title" for="__drawer">
<a href="../.." title="FlatBuffers Docs" class="md-nav__button md-logo" aria-label="FlatBuffers Docs" data-md-component="logo">
<img src="../../assets/flatbuffers_logo.svg" alt="logo">
</a>
FlatBuffers Docs
</label>
<div class="md-nav__source">
<a href="https://github.com/google/flatbuffers" title="Go to repository" class="md-source" data-md-component="source">
<div class="md-source__icon md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!--! Font Awesome Free 7.0.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path fill="currentColor" d="M173.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6m-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3m44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9M252.8 8C114.1 8 8 113.3 8 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C436.2 457.8 504 362.9 504 252 504 113.3 391.5 8 252.8 8M105.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1m-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7m32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1m-11.4-14.7c-1.6 1-1.6 3.6 0 5.9s4.3 3.3 5.6 2.3c1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2"/></svg>
</div>
<div class="md-source__repository">
google/FlatBuffers
</div>
</a>
</div>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../.." class="md-nav__link">
<span class="md-ellipsis">
Overview
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../quick_start/" class="md-nav__link">
<span class="md-ellipsis">
Quick Start
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../tutorial/" class="md-nav__link">
<span class="md-ellipsis">
Tutorial
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle md-toggle--indeterminate" type="checkbox" id="__nav_4" >
<label class="md-nav__link" for="__nav_4" id="__nav_4_label" tabindex="0">
<span class="md-ellipsis">
Compiler (flatc)
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_4_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_4">
<span class="md-nav__icon md-icon"></span>
Compiler (flatc)
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../building/" class="md-nav__link">
<span class="md-ellipsis">
Building
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../flatc/" class="md-nav__link">
<span class="md-ellipsis">
Using
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle md-toggle--indeterminate" type="checkbox" id="__nav_5" >
<label class="md-nav__link" for="__nav_5" id="__nav_5_label" tabindex="0">
<span class="md-ellipsis">
Schema (.fbs)
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_5_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_5">
<span class="md-nav__icon md-icon"></span>
Schema (.fbs)
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../schema/" class="md-nav__link">
<span class="md-ellipsis">
Overview
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../evolution/" class="md-nav__link">
<span class="md-ellipsis">
Evolution
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../grammar/" class="md-nav__link">
<span class="md-ellipsis">
Grammar
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--active md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_6" checked>
<label class="md-nav__link" for="__nav_6" id="__nav_6_label" tabindex="0">
<span class="md-ellipsis">
Language Guides
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_6_label" aria-expanded="true">
<label class="md-nav__title" for="__nav_6">
<span class="md-nav__icon md-icon"></span>
Language Guides
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../c/" class="md-nav__link">
<span class="md-ellipsis">
C
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../cpp/" class="md-nav__link">
<span class="md-ellipsis">
C++
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../c_sharp/" class="md-nav__link">
<span class="md-ellipsis">
C#
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../dart/" class="md-nav__link">
<span class="md-ellipsis">
Dart
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../go/" class="md-nav__link">
<span class="md-ellipsis">
Go
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--active">
<input class="md-nav__toggle md-toggle" type="checkbox" id="__toc">
<label class="md-nav__link md-nav__link--active" for="__toc">
<span class="md-ellipsis">
Java
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<a href="./" class="md-nav__link md-nav__link--active">
<span class="md-ellipsis">
Java
</span>
</a>
<nav class="md-nav md-nav--secondary" aria-label="Table of contents">
<label class="md-nav__title" for="__toc">
<span class="md-nav__icon md-icon"></span>
Table of contents
</label>
<ul class="md-nav__list" data-md-component="toc" data-md-scrollfix>
<li class="md-nav__item">
<a href="#before-you-get-started" class="md-nav__link">
<span class="md-ellipsis">
Before you get started
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#flatbuffers-java-code-location" class="md-nav__link">
<span class="md-ellipsis">
FlatBuffers Java code location
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#testing-the-flatbuffers-java-libraries" class="md-nav__link">
<span class="md-ellipsis">
Testing the FlatBuffers Java libraries
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#using-the-flatbuffers-java-library" class="md-nav__link">
<span class="md-ellipsis">
Using the FlatBuffers Java library
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#storing-dictionaries-in-a-flatbuffer" class="md-nav__link">
<span class="md-ellipsis">
Storing dictionaries in a FlatBuffer
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#text-parsing" class="md-nav__link">
<span class="md-ellipsis">
Text parsing
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../javascript/" class="md-nav__link">
<span class="md-ellipsis">
JavaScript
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../kotlin/" class="md-nav__link">
<span class="md-ellipsis">
Kotlin
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../lobster/" class="md-nav__link">
<span class="md-ellipsis">
Lobster
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../lua/" class="md-nav__link">
<span class="md-ellipsis">
Lua
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../php/" class="md-nav__link">
<span class="md-ellipsis">
PHP
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../python/" class="md-nav__link">
<span class="md-ellipsis">
Python
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../rust/" class="md-nav__link">
<span class="md-ellipsis">
Rust
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../swift/" class="md-nav__link">
<span class="md-ellipsis">
Swift
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../typescript/" class="md-nav__link">
<span class="md-ellipsis">
TypeScript
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../../support/" class="md-nav__link">
<span class="md-ellipsis">
Supported Configurations
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../white_paper/" class="md-nav__link">
<span class="md-ellipsis">
White Paper
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle md-toggle--indeterminate" type="checkbox" id="__nav_9" >
<label class="md-nav__link" for="__nav_9" id="__nav_9_label" tabindex="0">
<span class="md-ellipsis">
Advanced
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_9_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_9">
<span class="md-nav__icon md-icon"></span>
Advanced
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../internals/" class="md-nav__link">
<span class="md-ellipsis">
FlatBuffers Internals
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../intermediate_representation/" class="md-nav__link">
<span class="md-ellipsis">
Intermediate Representation
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../annotation/" class="md-nav__link">
<span class="md-ellipsis">
Annotating Buffers (.afb)
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../benchmarks/" class="md-nav__link">
<span class="md-ellipsis">
Benchmarks
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../../flexbuffers/" class="md-nav__link">
<span class="md-ellipsis">
FlexBuffers (Schema-less version)
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../contributing/" class="md-nav__link">
<span class="md-ellipsis">
Contributing
</span>
</a>
</li>
</ul>
</nav>
</div>
</div>
</div>
<div class="md-sidebar md-sidebar--secondary" data-md-component="sidebar" data-md-type="toc" >
<div class="md-sidebar__scrollwrap">
<div class="md-sidebar__inner">
<nav class="md-nav md-nav--secondary" aria-label="Table of contents">
<label class="md-nav__title" for="__toc">
<span class="md-nav__icon md-icon"></span>
Table of contents
</label>
<ul class="md-nav__list" data-md-component="toc" data-md-scrollfix>
<li class="md-nav__item">
<a href="#before-you-get-started" class="md-nav__link">
<span class="md-ellipsis">
Before you get started
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#flatbuffers-java-code-location" class="md-nav__link">
<span class="md-ellipsis">
FlatBuffers Java code location
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#testing-the-flatbuffers-java-libraries" class="md-nav__link">
<span class="md-ellipsis">
Testing the FlatBuffers Java libraries
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#using-the-flatbuffers-java-library" class="md-nav__link">
<span class="md-ellipsis">
Using the FlatBuffers Java library
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#storing-dictionaries-in-a-flatbuffer" class="md-nav__link">
<span class="md-ellipsis">
Storing dictionaries in a FlatBuffer
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#text-parsing" class="md-nav__link">
<span class="md-ellipsis">
Text parsing
</span>
</a>
</li>
</ul>
</nav>
</div>
</div>
</div>
<div class="md-content" data-md-component="content">
<article class="md-content__inner md-typeset">
<a href="https://github.com/google/flatbuffers/edit/master/docs/source/languages/java.md" title="Edit this page" class="md-content__button md-icon" rel="edit">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M10 20H6V4h7v5h5v3.1l2-2V8l-6-6H6c-1.1 0-2 .9-2 2v16c0 1.1.9 2 2 2h4zm10.2-7c.1 0 .3.1.4.2l1.3 1.3c.2.2.2.6 0 .8l-1 1-2.1-2.1 1-1c.1-.1.2-.2.4-.2m0 3.9L14.1 23H12v-2.1l6.1-6.1z"/></svg>
</a>
<h1 id="flatbuffers_guide_use_java">Use in Java</h1>
<h2 id="before-you-get-started">Before you get started</h2>
<p>Before diving into the FlatBuffers usage in Java, it should be noted that
the <a href="../../tutorial/">Tutorial</a> page has a complete guide to
general FlatBuffers usage in all of the supported languages (including Java).
This page is designed to cover the nuances of FlatBuffers usage,
specific to Java.</p>
<p>You should also have read the <a href="../../building/">Building</a>
documentation to build <code>flatc</code> and should be familiar with
<a href="../../flatc/">Using the schema compiler</a> and
<a href="../../schema/">Writing a schema</a>.</p>
<h2 id="flatbuffers-java-code-location">FlatBuffers Java code location</h2>
<p>The code for the FlatBuffers Java library can be found at
<code>flatbuffers/java/com/google/flatbuffers</code>. You can browse the library on the
<a href="https://github.com/google/flatbuffers/tree/master/
java/com/google/flatbuffers">FlatBuffers GitHub page</a>.</p>
<h2 id="testing-the-flatbuffers-java-libraries">Testing the FlatBuffers Java libraries</h2>
<p>The code to test the libraries can be found at <code>flatbuffers/tests</code>.</p>
<p>The test code for Java is located in <a href="https://github.com/google
/flatbuffers/blob/master/tests/JavaTest.java">JavaTest.java</a>.</p>
<p>To run the tests, use either <a href="https://github.com/google/
flatbuffers/blob/master/tests/JavaTest.sh">JavaTest.sh</a> or <a href="https://github.com/
google/flatbuffers/blob/master/tests/JavaTest.bat">JavaTest.bat</a>, depending on your operating
system.</p>
<p><em>Note: These scripts require that <a href="https://www.oracle.com/java/index.html">Java</a>
is installed.</em></p>
<h2 id="using-the-flatbuffers-java-library">Using the FlatBuffers Java library</h2>
<p><em>Note: See <a href="../../tutorial/">Tutorial</a> for a more in-depth
example of how to use FlatBuffers in Java.</em></p>
<p>FlatBuffers supports reading and writing binary FlatBuffers in Java.</p>
<p>To use FlatBuffers in your own code, first generate Java classes from your
schema with the <code>--java</code> option to <code>flatc</code>.
Then you can include both FlatBuffers and the generated code to read
or write a FlatBuffer.</p>
<p>For example, here is how you would read a FlatBuffer binary file in Java:
First, import the library and generated code. Then, you read a FlatBuffer binary
file into a <code>byte[]</code>. You then turn the <code>byte[]</code> into a <code>ByteBuffer</code>, which you
pass to the <code>getRootAsMyRootType</code> function:</p>
<div class="highlight"><pre><span></span><code><span class="w"> </span><span class="kn">import</span><span class="w"> </span><span class="nn">MyGame.Example.*</span><span class="p">;</span>
<span class="w"> </span><span class="kn">import</span><span class="w"> </span><span class="nn">com.google.flatbuffers.FlatBufferBuilder</span><span class="p">;</span>
<span class="w"> </span><span class="c1">// This snippet ignores exceptions for brevity.</span>
<span class="w"> </span><span class="n">File</span><span class="w"> </span><span class="n">file</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">File</span><span class="p">(</span><span class="s">&quot;monsterdata_test.mon&quot;</span><span class="p">);</span>
<span class="w"> </span><span class="n">RandomAccessFile</span><span class="w"> </span><span class="n">f</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">RandomAccessFile</span><span class="p">(</span><span class="n">file</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;r&quot;</span><span class="p">);</span>
<span class="w"> </span><span class="kt">byte</span><span class="o">[]</span><span class="w"> </span><span class="n">data</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="kt">byte</span><span class="o">[</span><span class="p">(</span><span class="kt">int</span><span class="p">)</span><span class="n">f</span><span class="p">.</span><span class="na">length</span><span class="p">()</span><span class="o">]</span><span class="p">;</span>
<span class="w"> </span><span class="n">f</span><span class="p">.</span><span class="na">readFully</span><span class="p">(</span><span class="n">data</span><span class="p">);</span>
<span class="w"> </span><span class="n">f</span><span class="p">.</span><span class="na">close</span><span class="p">();</span>
<span class="w"> </span><span class="n">ByteBuffer</span><span class="w"> </span><span class="n">bb</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">ByteBuffer</span><span class="p">.</span><span class="na">wrap</span><span class="p">(</span><span class="n">data</span><span class="p">);</span>
<span class="w"> </span><span class="n">Monster</span><span class="w"> </span><span class="n">monster</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">Monster</span><span class="p">.</span><span class="na">getRootAsMonster</span><span class="p">(</span><span class="n">bb</span><span class="p">);</span>
</code></pre></div>
<p>Now you can access the data from the <code>Monster monster</code>:</p>
<div class="highlight"><pre><span></span><code><span class="w"> </span><span class="kt">short</span><span class="w"> </span><span class="n">hp</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">monster</span><span class="p">.</span><span class="na">hp</span><span class="p">();</span>
<span class="w"> </span><span class="n">Vec3</span><span class="w"> </span><span class="n">pos</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">monster</span><span class="p">.</span><span class="na">pos</span><span class="p">();</span>
</code></pre></div>
<h2 id="storing-dictionaries-in-a-flatbuffer">Storing dictionaries in a FlatBuffer</h2>
<p>FlatBuffers doesn't support dictionaries natively, but there is support to
emulate their behavior with vectors and binary search, which means you
can have fast lookups directly from a FlatBuffer without having to unpack
your data into a <code>Dictionary</code> or similar.</p>
<p>To use it:
- Designate one of the fields in a table as the "key" field. You do this
by setting the <code>key</code> attribute on this field, e.g.
<code>name:string (key)</code>.
You may only have one key field, and it must be of string or scalar type.
- Write out tables of this type as usual, collect their offsets in an
array.
- Instead of calling standard generated method,
e.g.: <code>Monster.createTestarrayoftablesVector</code>,
call <code>createSortedVectorOfTables</code> (from the <code>FlatBufferBuilder</code> object).
which will first sort all offsets such that the tables they refer to
are sorted by the key field, then serialize it.
- Now when you're accessing the FlatBuffer, you can use
the <code>ByKey</code> accessor to access elements of the vector, e.g.:
<code>monster.testarrayoftablesByKey("Frodo")</code>.
which returns an object of the corresponding table type,
or <code>null</code> if not found.
<code>ByKey</code> performs a binary search, so should have a similar
speed to <code>Dictionary</code>, though may be faster because of better caching.
<code>ByKey</code> only works if the vector has been sorted, it will
likely not find elements if it hasn't been sorted.</p>
<h2 id="text-parsing">Text parsing</h2>
<p>There currently is no support for parsing text (Schema's and JSON) directly
from Java, though you could use the C++ parser through native call
interfaces available to each language. Please see the
C++ documentation for more on text parsing.</p>
<p><br></p>
</article>
</div>
<script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script>
<script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script>
</div>
</main>
<footer class="md-footer">
<nav class="md-footer__inner md-grid" aria-label="Footer" >
<a href="../go/" class="md-footer__link md-footer__link--prev" aria-label="Previous: Go">
<div class="md-footer__button md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M20 11v2H8l5.5 5.5-1.42 1.42L4.16 12l7.92-7.92L13.5 5.5 8 11z"/></svg>
</div>
<div class="md-footer__title">
<span class="md-footer__direction">
Previous
</span>
<div class="md-ellipsis">
Go
</div>
</div>
</a>
<a href="../javascript/" class="md-footer__link md-footer__link--next" aria-label="Next: JavaScript">
<div class="md-footer__title">
<span class="md-footer__direction">
Next
</span>
<div class="md-ellipsis">
JavaScript
</div>
</div>
<div class="md-footer__button md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M4 11v2h12l-5.5 5.5 1.42 1.42L19.84 12l-7.92-7.92L10.5 5.5 16 11z"/></svg>
</div>
</a>
</nav>
<div class="md-footer-meta md-typeset">
<div class="md-footer-meta__inner md-grid">
<div class="md-copyright">
<div class="md-copyright__highlight">
Copyright &copy; 2025 Google
</div>
Made with
<a href="https://squidfunk.github.io/mkdocs-material/" target="_blank" rel="noopener">
Material for MkDocs
</a>
</div>
<div class="md-social">
<a href="https://github.com/google/flatbuffers" target="_blank" rel="noopener" title="github.com" class="md-social__link">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!--! Font Awesome Free 7.0.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path fill="currentColor" d="M173.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6m-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3m44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9M252.8 8C114.1 8 8 113.3 8 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C436.2 457.8 504 362.9 504 252 504 113.3 391.5 8 252.8 8M105.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1m-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7m32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1m-11.4-14.7c-1.6 1-1.6 3.6 0 5.9s4.3 3.3 5.6 2.3c1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2"/></svg>
</a>
<a href="https:///discord.gg/6qgKs3R" target="_blank" rel="noopener" title="" class="md-social__link">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 576 512"><!--! Font Awesome Free 7.0.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path fill="currentColor" d="M492.5 69.8c-.2-.3-.4-.6-.8-.7-38.1-17.5-78.4-30-119.7-37.1-.4-.1-.8 0-1.1.1s-.6.4-.8.8c-5.5 9.9-10.5 20.2-14.9 30.6-44.6-6.8-89.9-6.8-134.4 0-4.5-10.5-9.5-20.7-15.1-30.6-.2-.3-.5-.6-.8-.8s-.7-.2-1.1-.2C162.5 39 122.2 51.5 84.1 69c-.3.1-.6.4-.8.7C7.1 183.5-13.8 294.6-3.6 404.2c0 .3.1.5.2.8s.3.4.5.6c44.4 32.9 94 58 146.8 74.2.4.1.8.1 1.1 0s.7-.4.9-.7c11.3-15.4 21.4-31.8 30-48.8.1-.2.2-.5.2-.8s0-.5-.1-.8-.2-.5-.4-.6-.4-.3-.7-.4c-15.8-6.1-31.2-13.4-45.9-21.9-.3-.2-.5-.4-.7-.6s-.3-.6-.3-.9 0-.6.2-.9.3-.5.6-.7c3.1-2.3 6.2-4.7 9.1-7.1.3-.2.6-.4.9-.4s.7 0 1 .1c96.2 43.9 200.4 43.9 295.5 0 .3-.1.7-.2 1-.2s.7.2.9.4c2.9 2.4 6 4.9 9.1 7.2.2.2.4.4.6.7s.2.6.2.9-.1.6-.3.9-.4.5-.6.6c-14.7 8.6-30 15.9-45.9 21.8-.2.1-.5.2-.7.4s-.3.4-.4.7-.1.5-.1.8.1.5.2.8c8.8 17 18.8 33.3 30 48.8.2.3.6.6.9.7s.8.1 1.1 0c52.9-16.2 102.6-41.3 147.1-74.2.2-.2.4-.4.5-.6s.2-.5.2-.8c12.3-126.8-20.5-236.9-86.9-334.5zm-302 267.7c-29 0-52.8-26.6-52.8-59.2s23.4-59.2 52.8-59.2c29.7 0 53.3 26.8 52.8 59.2 0 32.7-23.4 59.2-52.8 59.2m195.4 0c-29 0-52.8-26.6-52.8-59.2s23.4-59.2 52.8-59.2c29.7 0 53.3 26.8 52.8 59.2 0 32.7-23.2 59.2-52.8 59.2"/></svg>
</a>
<a href="https://twitter.com/dbaileychess" target="_blank" rel="noopener" title="twitter.com" class="md-social__link">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!--! Font Awesome Free 7.0.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path fill="currentColor" d="M357.2 48h70.6L273.6 224.2 455 464H313L201.7 318.6 74.5 464H3.8l164.9-188.5L-5.2 48h145.6l100.5 132.9zm-24.8 373.8h39.1L119.1 88h-42z"/></svg>
</a>
</div>
</div>
</div>
</footer>
</div>
<div class="md-dialog" data-md-component="dialog">
<div class="md-dialog__inner md-typeset"></div>
</div>
<script id="__config" type="application/json">{"base": "../..", "features": ["content.code.annotate", "content.tabs.link", "navigation.expand", "navigation.footer", "header.autohide", "content.action.edit"], "search": "../../assets/javascripts/workers/search.d50fe291.min.js", "tags": null, "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}, "version": null}</script>
<script src="../../assets/javascripts/bundle.50899def.min.js"></script>
</body>
</html>