<!--
* Copyright (c) 2017, 2020 IBM Corp. and others
*
* This program and the accompanying materials are made
* available under the terms of the Eclipse Public License 2.0
* which accompanies this distribution and is available at
* https://www.eclipse.org/legal/epl-2.0/ or the Apache
* License, Version 2.0 which accompanies this distribution and
* is available at https://www.apache.org/licenses/LICENSE-2.0.
*
* This Source Code may also be made available under the
* following Secondary Licenses when the conditions for such
* availability set forth in the Eclipse Public License, v. 2.0
* are satisfied: GNU General Public License, version 2 with
* the GNU Classpath Exception [1] and GNU General Public
* License, version 2 with the OpenJDK Assembly Exception [2].
*
* [1] https://www.gnu.org/software/classpath/license.html
* [2] http://openjdk.java.net/legal/assembly-exception.html
*
* SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH
* Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
-->


<!DOCTYPE html>
<html lang="en" class="no-js">
  <head>
    
      <meta charset="utf-8">
      <meta name="viewport" content="width=device-width,initial-scale=1">
      <meta http-equiv="x-ua-compatible" content="ie=edge">
      
        <meta name="description" content="Eclipse OpenJ9 documentation">
      
      
        <link rel="canonical" href="https://www.eclipse.org/openj9/docs/introduction/">
      
      
        <meta name="lang:clipboard.copy" content="">
      
        <meta name="lang:clipboard.copied" content="">
      
        <meta name="lang:search.language" content="">
      
        <meta name="lang:search.pipeline.stopwords" content="">
      
        <meta name="lang:search.pipeline.trimmer" content="">
      
        <meta name="lang:search.result.none" content="">
      
        <meta name="lang:search.result.one" content="">
      
        <meta name="lang:search.result.other" content="">
      
        <meta name="lang:search.tokenizer" content="">
      
      <link rel="shortcut icon" href="../cr/oj9logo_img9.ico">
      <meta name="generator" content="mkdocs-1.0.4, mkdocs-material-3.0.4">
    
    
        <title>Getting started -  </title>
      
    
      <link rel="stylesheet" href="../assets/stylesheets/application.1b62728e.css">
      
        <link rel="stylesheet" href="../assets/stylesheets/application-palette.a8b3c06d.css">
      
      
        <meta name="theme-color" content="#00bcd4">
      
    
      <script src="../assets/javascripts/modernizr.268332fc.js"></script>
    
    
        <link href="https://fonts.gstatic.com" rel="preconnect" crossorigin>
        <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Roboto:300,400,400i,700|Roboto+Mono">
        <style>body,input{font-family:"Roboto","Helvetica Neue",Helvetica,Arial,sans-serif}code,kbd,pre{font-family:"Roboto Mono","Courier New",Courier,monospace}</style>
      
    
    <link rel="stylesheet" href="../assets/fonts/material-icons.css">
    
      <link rel="stylesheet" href="../stylesheets/oj9.css">
    
    
<!-- Google Tag Manager -->
<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f (https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore%28j,f) );
})(window,document,'script','dataLayer','GTM-5WLCZXC');</script>
<!-- End Google Tag Manager -->  
  </head>
  
    
    <body dir="" data-md-color-primary="cyan" data-md-color-accent="cyan">
  
    <svg class="md-svg">
      <defs>
        
        
          <svg xmlns="http://www.w3.org/2000/svg" width="416" height="448" viewBox="0 0 416 448" id="__github"><path fill="currentColor" d="M160 304q0 10-3.125 20.5t-10.75 19T128 352t-18.125-8.5-10.75-19T96 304t3.125-20.5 10.75-19T128 256t18.125 8.5 10.75 19T160 304zm160 0q0 10-3.125 20.5t-10.75 19T288 352t-18.125-8.5-10.75-19T256 304t3.125-20.5 10.75-19T288 256t18.125 8.5 10.75 19T320 304zm40 0q0-30-17.25-51T296 232q-10.25 0-48.75 5.25Q229.5 240 208 240t-39.25-2.75Q130.75 232 120 232q-29.5 0-46.75 21T56 304q0 22 8 38.375t20.25 25.75 30.5 15 35 7.375 37.25 1.75h42q20.5 0 37.25-1.75t35-7.375 30.5-15 20.25-25.75T360 304zm56-44q0 51.75-15.25 82.75-9.5 19.25-26.375 33.25t-35.25 21.5-42.5 11.875-42.875 5.5T212 416q-19.5 0-35.5-.75t-36.875-3.125-38.125-7.5-34.25-12.875T37 371.5t-21.5-28.75Q0 312 0 260q0-59.25 34-99-6.75-20.5-6.75-42.5 0-29 12.75-54.5 27 0 47.5 9.875t47.25 30.875Q171.5 96 212 96q37 0 70 8 26.25-20.5 46.75-30.25T376 64q12.75 25.5 12.75 54.5 0 21.75-6.75 42 34 40 34 99.5z"/></svg>
        
      </defs>
    </svg>
    <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" data-md-component="overlay" for="__drawer"></label>
    
      <a href="../#eclipse-openj9" tabindex="1" class="md-skip">
        
      </a>
    
    
      <!--
* Copyright (c) 2017, 2020 IBM Corp. and others
*
* This program and the accompanying materials are made
* available under the terms of the Eclipse Public License 2.0
* which accompanies this distribution and is available at
* https://www.eclipse.org/legal/epl-2.0/ or the Apache
* License, Version 2.0 which accompanies this distribution and
* is available at https://www.apache.org/licenses/LICENSE-2.0.
*
* This Source Code may also be made available under the
* following Secondary Licenses when the conditions for such
* availability set forth in the Eclipse Public License, v. 2.0
* are satisfied: GNU General Public License, version 2 with
* the GNU Classpath Exception [1] and GNU General Public
* License, version 2 with the OpenJDK Assembly Exception [2].
*
* [1] https://www.gnu.org/software/classpath/license.html
* [2] http://openjdk.java.net/legal/assembly-exception.html
*
* SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH
* Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
-->
<header class="md-header" data-md-component="header">
    <nav class="md-header-nav md-grid">
      <div class="md-flex">
        <div class="md-flex__cell md-flex__cell--shrink">
          <a href="https://www.eclipse.org/openj9/docs" title=" " class="md-header-nav__button md-logo">
            
              <img src="../cr/openj9_6b.png">
            
          </a>
        </div>
        <div class="md-flex__cell md-flex__cell--shrink">
          <label class="md-icon md-icon--menu md-header-nav__button" for="__drawer"></label>
        </div>
        <div class="md-flex__cell md-flex__cell--stretch">
          <div class="md-flex__ellipsis md-header-nav__title" data-md-component="title">
          </div>
        </div>
        <div class="md-flex__cell md-flex__cell--shrink">
          
            
              <label class="md-icon md-icon--search md-header-nav__button" for="search"></label>
              
<div class="md-search" data-md-component="search" role="dialog">
  <label class="md-search__overlay" for="__search"></label>
  <div class="md-search__inner" role="search">
    <form class="md-search__form" name="search">
      <input type="text" class="md-search__input" name="query" placeholder="Search" autocapitalize="off" autocorrect="off" autocomplete="off" spellcheck="false" data-md-component="query" data-md-state="active">
      <label class="md-icon md-search__icon" for="__search"></label>
      <button type="reset" class="md-icon md-search__icon" data-md-component="reset" tabindex="-1">
        &#xE5CD;
      </button>
    </form>
    <div class="md-search__output">
      <div class="md-search__scrollwrap" data-md-scrollfix>
        <div class="md-search-result" data-md-component="result">
          <div class="md-search-result__meta">
            
          </div>
          <ol class="md-search-result__list"></ol>
        </div>
      </div>
    </div>
  </div>
</div>
            
          
        </div>
        
          <div class="md-flex__cell md-flex__cell--shrink">
            <div class="md-header-nav__source">
              

<a href="https://github.com/eclipse/openj9-docs/" title="Go to repository" class="md-source" data-md-source="github">
  
    <div class="md-source__icon">
      <svg viewBox="0 0 24 24" width="24" height="24">
        <use xlink:href="#__github" width="24" height="24"></use>
      </svg>
    </div>
  
  <div class="md-source__repository">
    GitHub
  </div>
</a>
            </div>
          </div>
        
  
        <!-- Eclipse Incubator link -->
        <div class="md-flex__cell md-flex__cell--shrink">
          <a href="http://wiki.eclipse.org/Development_Resources/Process_Guidelines/What_is_Incubation" target="_blank"><img class="egg" src="../cr/egg-incubation.png" alt="Eclipse Incubation"></a>
        </div>  
  
      </div>
    </nav>
  </header>
  
    
    <div class="md-container">
      
        
      <main class="md-main">
        <div class="md-main__inner md-grid" data-md-component="container">
          
            
              <div class="md-sidebar md-sidebar--primary" data-md-component="navigation">
                <div class="md-sidebar__scrollwrap">
                  <div class="md-sidebar__inner">
                    <nav class="md-nav md-nav--primary" data-md-level="0">
  <label class="md-nav__title md-nav__title--site" for="__drawer">
    <a href="https://www.eclipse.org/openj9/docs" title=" " class="md-nav__button md-logo">
      
        <img src="../cr/openj9_6b.png" width="48" height="48">
      
    </a>
     
  </label>
  
    <div class="md-nav__source">
      

<a href="https://github.com/eclipse/openj9-docs/" title="Go to repository" class="md-source" data-md-source="github">
  
    <div class="md-source__icon">
      <svg viewBox="0 0 24 24" width="24" height="24">
        <use xlink:href="#__github" width="24" height="24"></use>
      </svg>
    </div>
  
  <div class="md-source__repository">
    GitHub
  </div>
</a>
    </div>
  
  <ul class="md-nav__list" data-md-scrollfix>
    
      
  <li class="md-nav__item">
    <a href=".." title="About" class="md-nav__link">
      About
    </a>
  </li>

    
  <li class="md-nav__item">
    <a href="../adoptopenjdk/" title="AdoptOpenJDK builds" class="md-nav__link">
      AdoptOpenJDK builds
    </a>
  </li>

    
  <li class="md-nav__item md-nav__item--active">
    
    <input class="md-toggle md-nav__toggle" data-md-toggle="toc" type="checkbox" id="__toc">
    
      
      <label class="md-nav__link md-nav__link--active" for="__toc">
        Getting started
      </label>
    
    <a href="./" title="Getting started" class="md-nav__link md-nav__link--active">
      Getting started
    </a>
    
      
<nav class="md-nav md-nav--secondary">
  
  
    <label class="md-nav__title" for="__toc">On this page ...</label>
    <ul class="md-nav__list" data-md-scrollfix>
      
        <li class="md-nav__item">
  <a href="#configuring-your-system" class="md-nav__link">
    Configuring your system
  </a>
  
</li>
      
        <li class="md-nav__item">
  <a href="#performance-tuning" class="md-nav__link">
    Performance tuning
  </a>
  
    <nav class="md-nav">
      <ul class="md-nav__list">
        
          <li class="md-nav__item">
  <a href="#garbage-collection-policies" class="md-nav__link">
    Garbage collection policies
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#class-data-sharing" class="md-nav__link">
    Class data sharing
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#native-data-operations" class="md-nav__link">
    Native data operations
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#cloud-optimizations" class="md-nav__link">
    Cloud optimizations
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#cryptographic-operations" class="md-nav__link">
    Cryptographic operations
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#exploiting-gpus" class="md-nav__link">
    Exploiting GPUs
  </a>
  
</li>
        
      </ul>
    </nav>
  
</li>
      
        <li class="md-nav__item">
  <a href="#runtime-options" class="md-nav__link">
    Runtime options
  </a>
  
</li>
      
        <li class="md-nav__item">
  <a href="#default-settings" class="md-nav__link">
    Default settings
  </a>
  
</li>
      
        <li class="md-nav__item">
  <a href="#using-jlink" class="md-nav__link">
    Using Jlink
  </a>
  
</li>
      
        <li class="md-nav__item">
  <a href="#troubleshooting" class="md-nav__link">
    Troubleshooting
  </a>
  
</li>
      
      
    </ul>
  
</nav>
    
  </li>

    
  <li class="md-nav__item">
    <a href="../openj9_newuser/" title="New to OpenJ9?" class="md-nav__link">
      New to OpenJ9?
    </a>
  </li>

    
  <li class="md-nav__item md-nav__item--nested">
    
      <input class="md-toggle md-nav__toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5">
    
    <label class="md-nav__link" for="nav-5">
      Release notes
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="1">
      <label class="md-nav__title" for="nav-5">
        Release notes
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <li class="md-nav__item">
    <a href="../openj9_releases/" title="Overview" class="md-nav__link">
      Overview
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../version0.19/" title="Version 0.19.0" class="md-nav__link">
      Version 0.19.0
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../version0.18/" title="Version 0.18.1" class="md-nav__link">
      Version 0.18.1
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../version0.17/" title="Version 0.17.0" class="md-nav__link">
      Version 0.17.0
    </a>
  </li>

        
  <li class="md-nav__item md-nav__item--nested">
    
      <input class="md-toggle md-nav__toggle" data-md-toggle="nav-5-5" type="checkbox" id="nav-5-5">
    
    <label class="md-nav__link" for="nav-5-5">
      Earlier releases
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="2">
      <label class="md-nav__title" for="nav-5-5">
        Earlier releases
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <li class="md-nav__item">
    <a href="../version0.16/" title="Version 0.16.0" class="md-nav__link">
      Version 0.16.0
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../version0.15/" title="Version 0.15.1" class="md-nav__link">
      Version 0.15.1
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../version0.14/" title="Version 0.14.0" class="md-nav__link">
      Version 0.14.0
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../version0.13/" title="Version 0.13.0" class="md-nav__link">
      Version 0.13.0
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../version0.12/" title="Version 0.12.0" class="md-nav__link">
      Version 0.12.0
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../version0.11/" title="Version 0.11.0" class="md-nav__link">
      Version 0.11.0
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../version0.10/" title="Version 0.10.0" class="md-nav__link">
      Version 0.10.0
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../version0.9/" title="Version 0.9.0" class="md-nav__link">
      Version 0.9.0
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../version0.8/" title="Version 0.8.0" class="md-nav__link">
      Version 0.8.0
    </a>
  </li>

        
      </ul>
    </nav>
  </li>

        
      </ul>
    </nav>
  </li>

    
  <li class="md-nav__item">
    <a href="../gc/" title="Garbage Collection" class="md-nav__link">
      Garbage Collection
    </a>
  </li>

    
  <li class="md-nav__item">
    <a href="../jit/" title="JIT Compiler" class="md-nav__link">
      JIT Compiler
    </a>
  </li>

    
  <li class="md-nav__item">
    <a href="../jitserver/" title="JITServer (tech. preview)" class="md-nav__link">
      JITServer (tech. preview)
    </a>
  </li>

    
  <li class="md-nav__item">
    <a href="../aot/" title="AOT Compiler" class="md-nav__link">
      AOT Compiler
    </a>
  </li>

    
  <li class="md-nav__item md-nav__item--nested">
    
      <input class="md-toggle md-nav__toggle" data-md-toggle="nav-10" type="checkbox" id="nav-10">
    
    <label class="md-nav__link" for="nav-10">
      Class data sharing
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="1">
      <label class="md-nav__title" for="nav-10">
        Class data sharing
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <li class="md-nav__item">
    <a href="../shrc/" title="Overview" class="md-nav__link">
      Overview
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../shrc_diag_util/" title="Diagnostic cache utilities" class="md-nav__link">
      Diagnostic cache utilities
    </a>
  </li>

        
      </ul>
    </nav>
  </li>

    
  <li class="md-nav__item md-nav__item--nested">
    
      <input class="md-toggle md-nav__toggle" data-md-toggle="nav-11" type="checkbox" id="nav-11">
    
    <label class="md-nav__link" for="nav-11">
      Diagnostics
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="1">
      <label class="md-nav__title" for="nav-11">
        Diagnostics
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <li class="md-nav__item">
    <a href="../diag_overview/" title="Overview" class="md-nav__link">
      Overview
    </a>
  </li>

        
  <li class="md-nav__item md-nav__item--nested">
    
      <input class="md-toggle md-nav__toggle" data-md-toggle="nav-11-2" type="checkbox" id="nav-11-2">
    
    <label class="md-nav__link" for="nav-11-2">
      Dumps
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="2">
      <label class="md-nav__title" for="nav-11-2">
        Dumps
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <li class="md-nav__item">
    <a href="../dump_javadump/" title="Java dump" class="md-nav__link">
      Java dump
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dump_heapdump/" title="Heap dump" class="md-nav__link">
      Heap dump
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dump_systemdump/" title="System dump" class="md-nav__link">
      System dump
    </a>
  </li>

        
      </ul>
    </nav>
  </li>

        
  <li class="md-nav__item md-nav__item--nested">
    
      <input class="md-toggle md-nav__toggle" data-md-toggle="nav-11-3" type="checkbox" id="nav-11-3">
    
    <label class="md-nav__link" for="nav-11-3">
      Tools
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="2">
      <label class="md-nav__title" for="nav-11-3">
        Tools
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <li class="md-nav__item">
    <a href="../tool_jextract/" title="Dump extractor" class="md-nav__link">
      Dump extractor
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../tool_jdmpview/" title="Dump viewer" class="md-nav__link">
      Dump viewer
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../tool_traceformat/" title="Trace formatter" class="md-nav__link">
      Trace formatter
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../tool_builder/" title="Option builder" class="md-nav__link">
      Option builder
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../tool_jcmd/" title="Java command (jcmd) tool" class="md-nav__link">
      Java command (jcmd) tool
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../tool_jmap/" title="Java memory map (jmap) tool" class="md-nav__link">
      Java memory map (jmap) tool
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../tool_jps/" title="Java process status (jps)" class="md-nav__link">
      Java process status (jps)
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../tool_jstack/" title="Java stack (jstack) tool" class="md-nav__link">
      Java stack (jstack) tool
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../tool_jstat/" title="Java statistics monitoring (jstat) tool" class="md-nav__link">
      Java statistics monitoring (jstat) tool
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../tool_migration/" title="Switching to OpenJ9" class="md-nav__link">
      Switching to OpenJ9
    </a>
  </li>

        
      </ul>
    </nav>
  </li>

        
  <li class="md-nav__item md-nav__item--nested">
    
      <input class="md-toggle md-nav__toggle" data-md-toggle="nav-11-4" type="checkbox" id="nav-11-4">
    
    <label class="md-nav__link" for="nav-11-4">
      Interfaces
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="2">
      <label class="md-nav__title" for="nav-11-4">
        Interfaces
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <li class="md-nav__item">
    <a href="../interface_jvmti/" title="JVMTI" class="md-nav__link">
      JVMTI
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../interface_dtfj/" title="DTFJ" class="md-nav__link">
      DTFJ
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../interface_lang_management/" title="Language Management" class="md-nav__link">
      Language Management
    </a>
  </li>

        
      </ul>
    </nav>
  </li>

        
      </ul>
    </nav>
  </li>

    
  <li class="md-nav__item md-nav__item--nested">
    
      <input class="md-toggle md-nav__toggle" data-md-toggle="nav-12" type="checkbox" id="nav-12">
    
    <label class="md-nav__link" for="nav-12">
      Command-line options
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="1">
      <label class="md-nav__title" for="nav-12">
        Command-line options
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <li class="md-nav__item">
    <a href="../cmdline_specifying/" title="Specifying options" class="md-nav__link">
      Specifying options
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../cmdline_general/" title="Standard options" class="md-nav__link">
      Standard options
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../cmdline_migration/" title="Switching to OpenJ9" class="md-nav__link">
      Switching to OpenJ9
    </a>
  </li>

        
  <li class="md-nav__item md-nav__item--nested">
    
      <input class="md-toggle md-nav__toggle" data-md-toggle="nav-12-4" type="checkbox" id="nav-12-4">
    
    <label class="md-nav__link" for="nav-12-4">
      System property options
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="2">
      <label class="md-nav__title" for="nav-12-4">
        System property options
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <li class="md-nav__item">
    <a href="../d_jvm_commands/" title="Using System properties" class="md-nav__link">
      Using System properties
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dcomibmenableclasscaching/" title="-Dcom.ibm.enableClassCaching" class="md-nav__link">
      -Dcom.ibm.enableClassCaching
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dcomibmenablelegacydumpsecurity/" title="-Dcom.ibm.enableLegacyDumpSecurity" class="md-nav__link">
      -Dcom.ibm.enableLegacyDumpSecurity
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dcomibmenablelegacylogsecurity/" title="-Dcom.ibm.enableLegacyLogSecurity" class="md-nav__link">
      -Dcom.ibm.enableLegacyLogSecurity
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dcomibmenablelegacytracesecurity/" title="-Dcom.ibm.enableLegacyTraceSecurity" class="md-nav__link">
      -Dcom.ibm.enableLegacyTraceSecurity
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dcomibmgpudisable/" title="-Dcom.ibm.gpu.disable" class="md-nav__link">
      -Dcom.ibm.gpu.disable
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dcomibmgpuenable/" title="-Dcom.ibm.gpu.enable" class="md-nav__link">
      -Dcom.ibm.gpu.enable
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dcomibmgpuverbose/" title="-Dcom.ibm.gpu.verbose" class="md-nav__link">
      -Dcom.ibm.gpu.verbose
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dcomibmlangmanagementosmxbeaniscputime100ns/" title="-Dcom.ibm.lang.management.OperatingSystemMXBean.isCpuTime100ns" class="md-nav__link">
      -Dcom.ibm.lang.management.OperatingSystemMXBean.isCpuTime100ns
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dcomibmlangmanagementverbose/" title="-Dcom.ibm.lang.management.verbose" class="md-nav__link">
      -Dcom.ibm.lang.management.verbose
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dcomibmtoolsattachdirectory/" title="-Dcom.ibm.tools.attach.directory" class="md-nav__link">
      -Dcom.ibm.tools.attach.directory
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dcomibmtoolsattachdisplayname/" title="-Dcom.ibm.tools.attach.displayName" class="md-nav__link">
      -Dcom.ibm.tools.attach.displayName
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dcomibmtoolsattachenable/" title="-Dcom.ibm.tools.attach.enable" class="md-nav__link">
      -Dcom.ibm.tools.attach.enable
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dcomibmtoolsattachid/" title="-Dcom.ibm.tools.attach.id" class="md-nav__link">
      -Dcom.ibm.tools.attach.id
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dcomibmtoolsattachtimeout/" title="-Dcom.ibm.tools.attach.timeout" class="md-nav__link">
      -Dcom.ibm.tools.attach.timeout
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../dfileencoding/" title="-Dfile.encoding" class="md-nav__link">
      -Dfile.encoding
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../djavacompiler/" title="-Djava.compiler" class="md-nav__link">
      -Djava.compiler
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../djavalangstringsubstringnocopy/" title="-Djava.lang.string.substring.nocopy" class="md-nav__link">
      -Djava.lang.string.substring.nocopy
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../djavalangstringbuffergrowaggressively/" title="-Djava.lang.stringBuffer.growAggressively" class="md-nav__link">
      -Djava.lang.stringBuffer.growAggressively
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../djdknativecbc/" title="-Djdk.nativeCBC" class="md-nav__link">
      -Djdk.nativeCBC
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../djdknativechacha20/" title="-Djdk.nativeChaCha20" class="md-nav__link">
      -Djdk.nativeChaCha20
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../djdknativecrypto/" title="-Djdk.nativeCrypto" class="md-nav__link">
      -Djdk.nativeCrypto
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../djdknativedigest/" title="-Djdk.nativeDigest" class="md-nav__link">
      -Djdk.nativeDigest
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../djdknativegcm/" title="-Djdk.nativeGCM" class="md-nav__link">
      -Djdk.nativeGCM
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../djdknativersa/" title="-Djdk.nativeRSA" class="md-nav__link">
      -Djdk.nativeRSA
    </a>
  </li>

        
      </ul>
    </nav>
  </li>

        
  <li class="md-nav__item md-nav__item--nested">
    
      <input class="md-toggle md-nav__toggle" data-md-toggle="nav-12-5" type="checkbox" id="nav-12-5">
    
    <label class="md-nav__link" for="nav-12-5">
      JVM -X options
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="2">
      <label class="md-nav__title" for="nav-12-5">
        JVM -X options
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <li class="md-nav__item">
    <a href="../x_jvm_commands/" title="Using -X options" class="md-nav__link">
      Using -X options
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../x/" title="-X" class="md-nav__link">
      -X
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xaggressive/" title="-Xaggressive" class="md-nav__link">
      -Xaggressive
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xalwaysclassgc/" title="-Xalwaysclassgc" class="md-nav__link">
      -Xalwaysclassgc
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xaot/" title="-Xaot" class="md-nav__link">
      -Xaot
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xargencoding/" title="-Xargencoding" class="md-nav__link">
      -Xargencoding
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xbootclasspath/" title="-Xbootclasspath" class="md-nav__link">
      -Xbootclasspath
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xceehdlr/" title="-XCEEHDLR" class="md-nav__link">
      -XCEEHDLR
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xcheck/" title="-Xcheck" class="md-nav__link">
      -Xcheck
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xclassgc/" title="-Xclassgc" class="md-nav__link">
      -Xclassgc
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xcodecache/" title="-Xcodecache" class="md-nav__link">
      -Xcodecache
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xcodecachetotal/" title="-Xcodecachetotal" class="md-nav__link">
      -Xcodecachetotal
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xcomp/" title="-Xcomp" class="md-nav__link">
      -Xcomp
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xcompactexplicitgc/" title="-Xcompactexplicitgc" class="md-nav__link">
      -Xcompactexplicitgc
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xcompactgc/" title="-Xcompactgc" class="md-nav__link">
      -Xcompactgc
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xcompilationthreads/" title="-XcompilationThreads" class="md-nav__link">
      -XcompilationThreads
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xcompressedrefs/" title="-Xcompressedrefs" class="md-nav__link">
      -Xcompressedrefs
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xconcurrentbackground/" title="-Xconcurrentbackground" class="md-nav__link">
      -Xconcurrentbackground
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xconcurrentlevel/" title="-Xconcurrentlevel" class="md-nav__link">
      -Xconcurrentlevel
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xconcurrentslack/" title="-Xconcurrentslack" class="md-nav__link">
      -Xconcurrentslack
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xconmeter/" title="-Xconmeter" class="md-nav__link">
      -Xconmeter
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xenableexcessivegc/" title="-Xdisableexcessivegc" class="md-nav__link">
      -Xdisableexcessivegc
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xenableexplicitgc/" title="-Xdisableexplicitgc" class="md-nav__link">
      -Xdisableexplicitgc
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xdisablejavadump/" title="-Xdisablejavadump" class="md-nav__link">
      -Xdisablejavadump
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xenablestringconstantgc/" title="-Xdisablestringconstantgc" class="md-nav__link">
      -Xdisablestringconstantgc
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xdump/" title="-Xdump" class="md-nav__link">
      -Xdump
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xenableexcessivegc/" title="-Xenableexcessivegc" class="md-nav__link">
      -Xenableexcessivegc
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xenableexplicitgc/" title="-Xenableexplicitgc" class="md-nav__link">
      -Xenableexplicitgc
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xenablestringconstantgc/" title="-Xenablestringconstantgc" class="md-nav__link">
      -Xenablestringconstantgc
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xfastresolve/" title="-Xfastresolve" class="md-nav__link">
      -Xfastresolve
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xfuture/" title="-Xfuture" class="md-nav__link">
      -Xfuture
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xgc/" title="-Xgc" class="md-nav__link">
      -Xgc
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xgcsplitheap/" title="-Xgc:splitheap" class="md-nav__link">
      -Xgc:splitheap
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xgcpolicy/" title="-Xgcpolicy" class="md-nav__link">
      -Xgcpolicy
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xgcthreads/" title="-Xgcthreads" class="md-nav__link">
      -Xgcthreads
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xgcworkpackets/" title="-Xgcworkpackets" class="md-nav__link">
      -Xgcworkpackets
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xifa/" title="-Xifa" class="md-nav__link">
      -Xifa
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xint/" title="-Xint" class="md-nav__link">
      -Xint
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xss/" title="-Xiss" class="md-nav__link">
      -Xiss
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xjit/" title="-Xjit" class="md-nav__link">
      -Xjit
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xjni/" title="-Xjni" class="md-nav__link">
      -Xjni
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xlinenumbers/" title="-Xlinenumbers" class="md-nav__link">
      -Xlinenumbers
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xloa/" title="-Xloa" class="md-nav__link">
      -Xloa
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xloaminimum/" title="-Xloainitial" class="md-nav__link">
      -Xloainitial
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xloaminimum/" title="-Xloamaximum" class="md-nav__link">
      -Xloamaximum
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xloaminimum/" title="-Xloaminimum" class="md-nav__link">
      -Xloaminimum
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xlockreservation/" title="-XlockReservation" class="md-nav__link">
      -XlockReservation
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xlockword/" title="-Xlockword" class="md-nav__link">
      -Xlockword
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xlog/" title="-Xlog" class="md-nav__link">
      -Xlog
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xlp/" title="-Xlp" class="md-nav__link">
      -Xlp
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xlpcodecache/" title="-Xlp:codecache" class="md-nav__link">
      -Xlp:codecache
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xlpobjectheap/" title="-Xlp:objectheap" class="md-nav__link">
      -Xlp:objectheap
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmine/" title="-Xmaxe" class="md-nav__link">
      -Xmaxe
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xminf/" title="-Xmaxf" class="md-nav__link">
      -Xmaxf
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmint/" title="-Xmaxt" class="md-nav__link">
      -Xmaxt
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmca/" title="-Xmca" class="md-nav__link">
      -Xmca
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmca/" title="-Xmco" class="md-nav__link">
      -Xmco
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmcrs/" title="-Xmcrs" class="md-nav__link">
      -Xmcrs
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmine/" title="-Xmine" class="md-nav__link">
      -Xmine
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xminf/" title="-Xminf" class="md-nav__link">
      -Xminf
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmint/" title="-Xmint" class="md-nav__link">
      -Xmint
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmn/" title="-Xmn" class="md-nav__link">
      -Xmn
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmn/" title="-Xmns" class="md-nav__link">
      -Xmns
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmn/" title="-Xmnx" class="md-nav__link">
      -Xmnx
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmo/" title="-Xmo" class="md-nav__link">
      -Xmo
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmo/" title="-Xmoi" class="md-nav__link">
      -Xmoi
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmo/" title="-Xmos" class="md-nav__link">
      -Xmos
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmo/" title="-Xmox" class="md-nav__link">
      -Xmox
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmr/" title="-Xmr" class="md-nav__link">
      -Xmr
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmr/" title="-Xmrx" class="md-nav__link">
      -Xmrx
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xms/" title="-Xms" class="md-nav__link">
      -Xms
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xmso/" title="-Xmso" class="md-nav__link">
      -Xmso
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xms/" title="-Xmx" class="md-nav__link">
      -Xmx
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xaot/" title="-Xnoaot" class="md-nav__link">
      -Xnoaot
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xclassgc/" title="-Xnoclassgc" class="md-nav__link">
      -Xnoclassgc
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xcompactexplicitgc/" title="-Xnocompactexplicitgc" class="md-nav__link">
      -Xnocompactexplicitgc
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xcompactgc/" title="-Xnocompactgc" class="md-nav__link">
      -Xnocompactgc
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xcompressedrefs/" title="-Xnocompressedrefs" class="md-nav__link">
      -Xnocompressedrefs
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xjit/" title="-Xnojit" class="md-nav__link">
      -Xnojit
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xlinenumbers/" title="-Xnolinenumbers" class="md-nav__link">
      -Xnolinenumbers
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xloa/" title="-Xnoloa" class="md-nav__link">
      -Xnoloa
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xsigcatch/" title="-Xnosigcatch" class="md-nav__link">
      -Xnosigcatch
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xsigchain/" title="-Xnosigchain" class="md-nav__link">
      -Xnosigchain
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xnumanone/" title="-Xnuma:none" class="md-nav__link">
      -Xnuma:none
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xoptionsfile/" title="-Xoptionsfile" class="md-nav__link">
      -Xoptionsfile
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xquickstart/" title="-Xquickstart" class="md-nav__link">
      -Xquickstart
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xrs/" title="-Xrs" class="md-nav__link">
      -Xrs
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xsamplingexpirationtime/" title="-XsamplingExpirationTime" class="md-nav__link">
      -XsamplingExpirationTime
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xscdmx/" title="-Xscdmx" class="md-nav__link">
      -Xscdmx
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xscminaot/" title="-Xscmaxaot" class="md-nav__link">
      -Xscmaxaot
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xscminjitdata/" title="-Xscmaxjitdata" class="md-nav__link">
      -Xscmaxjitdata
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xscminaot/" title="-Xscminaot" class="md-nav__link">
      -Xscminaot
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xscminjitdata/" title="-Xscminjitdata" class="md-nav__link">
      -Xscminjitdata
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xscmx/" title="-Xscmx" class="md-nav__link">
      -Xscmx
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xshareclasses/" title="-Xshareclasses" class="md-nav__link">
      -Xshareclasses
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xsigcatch/" title="-Xsigcatch" class="md-nav__link">
      -Xsigcatch
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xsigchain/" title="-Xsigchain" class="md-nav__link">
      -Xsigchain
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xsignal/" title="-Xsignal" class="md-nav__link">
      -Xsignal
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xsoftmx/" title="-Xsoftmx" class="md-nav__link">
      -Xsoftmx
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xsoftrefthreshold/" title="-Xsoftrefthreshold" class="md-nav__link">
      -Xsoftrefthreshold
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xss/" title="-Xss" class="md-nav__link">
      -Xss
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xss/" title="-Xssi" class="md-nav__link">
      -Xssi
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xtgc/" title="-Xtgc" class="md-nav__link">
      -Xtgc
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xthr/" title="-Xthr" class="md-nav__link">
      -Xthr
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xtlhprefetch/" title="-XtlhPrefetch" class="md-nav__link">
      -XtlhPrefetch
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xtrace/" title="-Xtrace" class="md-nav__link">
      -Xtrace
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xtunevirtualized/" title="-Xtune:virtualized" class="md-nav__link">
      -Xtune:virtualized
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xverbosegclog/" title="-Xverbosegclog" class="md-nav__link">
      -Xverbosegclog
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xverify/" title="-Xverify" class="md-nav__link">
      -Xverify
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xzero/" title="-Xzero" class="md-nav__link">
      -Xzero
    </a>
  </li>

        
      </ul>
    </nav>
  </li>

        
  <li class="md-nav__item md-nav__item--nested">
    
      <input class="md-toggle md-nav__toggle" data-md-toggle="nav-12-6" type="checkbox" id="nav-12-6">
    
    <label class="md-nav__link" for="nav-12-6">
      JVM -XX options
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="2">
      <label class="md-nav__title" for="nav-12-6">
        JVM -XX options
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <li class="md-nav__item">
    <a href="../xx_jvm_commands/" title="Using -XX options" class="md-nav__link">
      Using -XX options
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxactiveprocessorcount/" title="-XXActiveProcessorCount" class="md-nav__link">
      -XXActiveProcessorCount
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxallowvmshutdown/" title="-XXallowvmshutdown" class="md-nav__link">
      -XXallowvmshutdown
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxclassrelationshipverifier/" title="-XX:[+|-]ClassRelationshipVerifier" class="md-nav__link">
      -XX:[+|-]ClassRelationshipVerifier
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxconcgcthreads/" title="-XX:ConcGCThreads" class="md-nav__link">
      -XX:ConcGCThreads
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxcodecachetotal/" title="-XX:codecachetotal" class="md-nav__link">
      -XX:codecachetotal
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxcompactstrings/" title="-XX:[+|-]CompactStrings" class="md-nav__link">
      -XX:[+|-]CompactStrings
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxdisableexplicitgc/" title="-XX:[+|-]DisableExplicitGC" class="md-nav__link">
      -XX:[+|-]DisableExplicitGC
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxdisclaimjitscratch/" title="-XX:[+|-]DisclaimJitScratch" class="md-nav__link">
      -XX:[+|-]DisclaimJitScratch
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxenablecpumonitor/" title="-XX:[+|-]EnableCPUMonitor" class="md-nav__link">
      -XX:[+|-]EnableCPUMonitor
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxexitonoutofmemoryerror/" title="-XX:[+|-]ExitOnOutOfMemoryError" class="md-nav__link">
      -XX:[+|-]ExitOnOutOfMemoryError
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxhandlesigxfsz/" title="-XX:[+|-]handleSIGXFSZ" class="md-nav__link">
      -XX:[+|-]handleSIGXFSZ
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxheapdumponoutofmemory/" title="-XX:[+|-]HeapDumpOnOutOfMemory" class="md-nav__link">
      -XX:[+|-]HeapDumpOnOutOfMemory
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxheapdumppath/" title="-XX:HeapDumpPath" class="md-nav__link">
      -XX:HeapDumpPath
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxheapmanagementmxbeancompatibility/" title="-XX:[+|-]HeapManagementMXBeanCompatibility" class="md-nav__link">
      -XX:[+|-]HeapManagementMXBeanCompatibility
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxidletuningcompactonidle/" title="-XX:[+|-]IdleTuningCompactOnIdle" class="md-nav__link">
      -XX:[+|-]IdleTuningCompactOnIdle
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxidletuninggconidle/" title="-XX:[+|-]IdleTuningGcOnIdle" class="md-nav__link">
      -XX:[+|-]IdleTuningGcOnIdle
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxidletuningminfreeheaponidle/" title="-XX:IdleTuningMinFreeHeapOnIdle" class="md-nav__link">
      -XX:IdleTuningMinFreeHeapOnIdle
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxidletuningminidlewaittime/" title="-XX:IdleTuningMinIdleWaitTime" class="md-nav__link">
      -XX:IdleTuningMinIdleWaitTime
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxignoreunrecognizedvmoptions/" title="-XX:[+|-]IgnoreUnrecognizedVMOptions" class="md-nav__link">
      -XX:[+|-]IgnoreUnrecognizedVMOptions
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxignoreunrecognizedxxcolonoptions/" title="-XX:[+|-]IgnoreUnrecognizedXXColonOptions" class="md-nav__link">
      -XX:[+|-]IgnoreUnrecognizedXXColonOptions
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxinitialrampercentage/" title="-XX:InitialRAMPercentage" class="md-nav__link">
      -XX:InitialRAMPercentage
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxinitialheapsize/" title="-XX:InitialHeapSize" class="md-nav__link">
      -XX:InitialHeapSize
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxinterleavememory/" title="-XX:[+|-]InterleaveMemory" class="md-nav__link">
      -XX:[+|-]InterleaveMemory
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxjitinlinewatches/" title="-XX:[+|-]JITInlineWatches" class="md-nav__link">
      -XX:[+|-]JITInlineWatches
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxlazysymbolresolution/" title="-XX:[+|-]LazySymbolResolution" class="md-nav__link">
      -XX:[+|-]LazySymbolResolution
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxmaxdirectmemorysize/" title="-XX:MaxDirectMemorySize" class="md-nav__link">
      -XX:MaxDirectMemorySize
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxinitialheapsize/" title="-XX:MaxHeapSize" class="md-nav__link">
      -XX:MaxHeapSize
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxinitialrampercentage/" title="-XX:MaxRAMPercentage" class="md-nav__link">
      -XX:MaxRAMPercentage
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxonoutofmemoryerror/" title="-XX:OnOutOfMemoryError" class="md-nav__link">
      -XX:OnOutOfMemoryError
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxnosuballoc32bitmem/" title="-XXnosuballoc32bitmem" class="md-nav__link">
      -XXnosuballoc32bitmem
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxpagealigndirectmemory/" title="-XX:[+|-]PageAlignDirectMemory" class="md-nav__link">
      -XX:[+|-]PageAlignDirectMemory
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxparallelcmsthreads/" title="-XX:ParallelCMSThreads" class="md-nav__link">
      -XX:ParallelCMSThreads
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxparallelgcthreads/" title="-XX:ParallelGCThreads" class="md-nav__link">
      -XX:ParallelGCThreads
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxpositiveidentityhash/" title="-XX:[+|-]PositiveIdentityHash" class="md-nav__link">
      -XX:[+|-]PositiveIdentityHash
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxprintcodecache/" title="-XX:[+|-]PrintCodeCache" class="md-nav__link">
      -XX:[+|-]PrintCodeCache
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxreadipinfoforras/" title="-XX:[+|-]ReadIPInfoForRAS" class="md-nav__link">
      -XX:[+|-]ReadIPInfoForRAS
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxreducecpumonitoroverhead/" title="-XX:[+|-]ReduceCPUMonitorOverhead" class="md-nav__link">
      -XX:[+|-]ReduceCPUMonitorOverhead
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxruntimeinstrumentation/" title="-XX:[+|-]RuntimeInstrumentation" class="md-nav__link">
      -XX:[+|-]RuntimeInstrumentation
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxsethwprefetch/" title="-XXsetHWPrefetch" class="md-nav__link">
      -XXsetHWPrefetch
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxshareanonymousclasses/" title="-XX:[+|-]ShareAnonymousClasses" class="md-nav__link">
      -XX:[+|-]ShareAnonymousClasses
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxshareclassesenablebci/" title="-XX:ShareClassesDisableBCI" class="md-nav__link">
      -XX:ShareClassesDisableBCI
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxshareclassesenablebci/" title="-XX:ShareClassesEnableBCI" class="md-nav__link">
      -XX:ShareClassesEnableBCI
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxsharedcachehardlimit/" title="-XX:SharedCacheHardLimit" class="md-nav__link">
      -XX:SharedCacheHardLimit
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxshareunsafeclasses/" title="-XX:[+|-]ShareUnsafeClasses" class="md-nav__link">
      -XX:[+|-]ShareUnsafeClasses
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxstacktraceinthrowable/" title="-XX:-StackTraceInThrowable" class="md-nav__link">
      -XX:-StackTraceInThrowable
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxtransparenthugepage/" title="-XX:[+|-]TransparentHugePage" class="md-nav__link">
      -XX:[+|-]TransparentHugePage
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxusecompressedoops/" title="-XX:[+|-]UseCompressedOops" class="md-nav__link">
      -XX:[+|-]UseCompressedOops
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxusecontainersupport/" title="-XX:[+|-]UseContainerSupport" class="md-nav__link">
      -XX:[+|-]UseContainerSupport
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxusegcstartuphints/" title="-XX:[+|-]UseGCStartupHints" class="md-nav__link">
      -XX:[+|-]UseGCStartupHints
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxusenogc/" title="-XX:[+|-]UseNoGC" class="md-nav__link">
      -XX:[+|-]UseNoGC
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxverboseverification/" title="-XX:[+|-]VerboseVerification" class="md-nav__link">
      -XX:[+|-]VerboseVerification
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../xxvmlockclassloader/" title="-XX:[+|-]VMLockClassLoader" class="md-nav__link">
      -XX:[+|-]VMLockClassLoader
    </a>
  </li>

        
      </ul>
    </nav>
  </li>

        
      </ul>
    </nav>
  </li>

    
  <li class="md-nav__item md-nav__item--nested">
    
      <input class="md-toggle md-nav__toggle" data-md-toggle="nav-13" type="checkbox" id="nav-13">
    
    <label class="md-nav__link" for="nav-13">
       Reference
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="1">
      <label class="md-nav__title" for="nav-13">
         Reference
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <li class="md-nav__item">
    <a href="../openj9_support/" title="Supported environments" class="md-nav__link">
      Supported environments
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../openj9_defaults/" title="Default settings" class="md-nav__link">
      Default settings
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../openj9_signals/" title="Signal handling" class="md-nav__link">
      Signal handling
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../openj9_directories/" title="Directory conventions" class="md-nav__link">
      Directory conventions
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../messages_intro/" title="OpenJ9 messages" class="md-nav__link">
      OpenJ9 messages
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../env_var/" title="Environment variables" class="md-nav__link">
      Environment variables
    </a>
  </li>

        
      </ul>
    </nav>
  </li>

    
  <li class="md-nav__item">
    <a href="../legal/" title="Legal" class="md-nav__link">
      Legal
    </a>
  </li>

    
  </ul>
</nav>
                  </div>
                </div>
              </div>
            
            
              <div class="md-sidebar md-sidebar--secondary" data-md-component="toc">
                <div class="md-sidebar__scrollwrap">
                  <div class="md-sidebar__inner">
                    
<nav class="md-nav md-nav--secondary">
  
  
    <label class="md-nav__title" for="__toc">On this page ...</label>
    <ul class="md-nav__list" data-md-scrollfix>
      
        <li class="md-nav__item">
  <a href="#configuring-your-system" class="md-nav__link">
    Configuring your system
  </a>
  
</li>
      
        <li class="md-nav__item">
  <a href="#performance-tuning" class="md-nav__link">
    Performance tuning
  </a>
  
    <nav class="md-nav">
      <ul class="md-nav__list">
        
          <li class="md-nav__item">
  <a href="#garbage-collection-policies" class="md-nav__link">
    Garbage collection policies
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#class-data-sharing" class="md-nav__link">
    Class data sharing
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#native-data-operations" class="md-nav__link">
    Native data operations
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#cloud-optimizations" class="md-nav__link">
    Cloud optimizations
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#cryptographic-operations" class="md-nav__link">
    Cryptographic operations
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#exploiting-gpus" class="md-nav__link">
    Exploiting GPUs
  </a>
  
</li>
        
      </ul>
    </nav>
  
</li>
      
        <li class="md-nav__item">
  <a href="#runtime-options" class="md-nav__link">
    Runtime options
  </a>
  
</li>
      
        <li class="md-nav__item">
  <a href="#default-settings" class="md-nav__link">
    Default settings
  </a>
  
</li>
      
        <li class="md-nav__item">
  <a href="#using-jlink" class="md-nav__link">
    Using Jlink
  </a>
  
</li>
      
        <li class="md-nav__item">
  <a href="#troubleshooting" class="md-nav__link">
    Troubleshooting
  </a>
  
</li>
      
      
    </ul>
  
</nav>
                  </div>
                </div>
              </div>
            
          
          <div class="md-content">
            <article class="md-content__inner md-typeset">
              
<!-- this adds 'pencil' icon to H1 so that you can edit the page directly in GitHub
                
                  <a href="https://github.com/eclipse/openj9-docs/edit/master/docs/introduction.md" title="Edit this page" class="md-icon md-content__icon">&#xE3C9;</a>
                
-->
                
                <!--
* Copyright (c) 2017, 2020 IBM Corp. and others
*
* This program and the accompanying materials are made
* available under the terms of the Eclipse Public License 2.0
* which accompanies this distribution and is available at
* https://www.eclipse.org/legal/epl-2.0/ or the Apache
* License, Version 2.0 which accompanies this distribution and
* is available at https://www.apache.org/licenses/LICENSE-2.0.
*
* This Source Code may also be made available under the
* following Secondary Licenses when the conditions for such
* availability set forth in the Eclipse Public License, v. 2.0
* are satisfied: GNU General Public License, version 2 with
* the GNU Classpath Exception [1] and GNU General Public
* License, version 2 with the OpenJDK Assembly Exception [2].
*
* [1] https://www.gnu.org/software/classpath/license.html
* [2] http://openjdk.java.net/legal/assembly-exception.html
*
* SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH
* Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
-->

<h1 id="eclipse-openj9">Eclipse OpenJ9</h1>
<p>OpenJ9 is a high performance, scalable, Java&trade; virtual machine (VM) implementation that is fully compliant with the <a href="https://docs.oracle.com/javase/specs/index.html">Java Virtual Machine Specification</a>.</p>
<p>At run time, the VM interprets the Java bytecode that is compiled by the Java compiler. The VM acts as a translator between the language and the underlying operating system and hardware. A Java program requires a specific VM to run on a particular platform, such as Linux&reg;, z/OS&reg;, or Windows&trade;.</p>
<p>This reference material provides information about the VM configuration and tuning options, together with the default settings.</p>
<h2 id="configuring-your-system">Configuring your system</h2>
<p>For normal operation, certain environment variables must be set at the operating system level. Depending on your system environment, you might also want to set other configuration options that allow the VM to exploit hardware and operating system features. Read <a href="https://www.ibm.com/support/knowledgecenter/SSYKE2_8.0.0/com.ibm.java.vm.80.doc/docs/j9_configure.html">Customizing your system</a> to learn more about the following options:</p>
<ul>
<li>Setting the PATH and CLASSPATH environment variable.</li>
<li>Setting the LIBPATH or LD_LIBRARY_PATH environment variable (AIX&reg; and Linux) to indicate where to find shared libraries.</li>
<li>Setting ulimits on AIX and Linux systems to ensure that the operating system allocates sufficient resources for your application.</li>
<li>Setting region size, BPXPRM parameters, and Language Environment&reg; runtime options on z/OS systems.</li>
<li>If your application allocates a large amount of memory and frequently accesses that memory, you might want to enable large page support on your system. See <a href="https://www.ibm.com/support/knowledgecenter/SSYKE2_8.0.0/com.ibm.java.vm.80.doc/docs/j9_configure_large_page.html">Configuring large page memory allocation</a>.</li>
<li>Configuring Dynamic LPAR support on AIX systems.</li>
</ul>
<p><i class="fa fa-pencil-square-o" aria-hidden="true"></i> <strong>Note:</strong> On macOS&reg; systems, you must set the DYLD_LIBRARY_PATH environment variable to indicate where to find shared libraries. In addition, to ensure there are sufficient resources for your application, you might need to increase system limits by using <code>launchctl</code>, <code>ulimit</code>, or <code>kern.&lt;VARIABLES&gt;</code>. For further instructions, refer to the documentation for your macOS release.</p>
<h2 id="performance-tuning">Performance tuning</h2>
<p>OpenJ9 is configured to start with a set of default options that provide the optimal runtime environment for Java applications with typical workloads. However, if your application is atypical, you can improve performance by tuning the OpenJ9 VM. You can also improve performance by enabling hardware features or using specific APIs in your application code.</p>
<h3 id="garbage-collection-policies">Garbage collection policies</h3>
<p>OpenJ9 includes several garbage collection policies. To learn more about these policies and the types of application workload that can benefit from them, see <a href="../gc/">Garbage Collection</a>.</p>
<h3 id="class-data-sharing">Class data sharing</h3>
<p>You can share class data between running VMs, which can reduce the startup time for a VM once the cache has been created. For more information, see <a href="../shrc/">Class Data Sharing</a>.</p>
<h3 id="native-data-operations">Native data operations</h3>
<p>If your Java application manipulates native data, consider writing your application to take advantage of methods in the Data Access Accelerator API.</p>
<h3 id="cloud-optimizations">Cloud optimizations</h3>
<p>To improve the performance of applications that run in containers, try setting the following tuning options:</p>
<ul>
<li>Use a shared classes cache (<code>-Xshareclasses -XX:SharedCacheHardLimit=200m -Xscmx60m</code>) with Ahead-Of-Time (AOT) compilation to improve your startup time. For more information, see <a href="../shrc/">Class Data Sharing</a> and <a href="../aot/">AOT Compiler</a>.</li>
<li>Use the <a href="../xtunevirtualized/">-Xtune:virtualized</a> option, which configures OpenJ9 for typical cloud deployments where VM guests are provisioned with a small number of virtual CPUs to maximize the number of applications that can be run. When enabled, OpenJ9 adapts its internal processes to reduce the amount of CPU consumed and trim down the memory footprint. These changes come at the expense of only a small loss in throughput.</li>
</ul>
<p>The OpenJ9 VM automatically detects when it is running in a docker container and uses a mechanism to detect when the VM is idle. When an idle state is detected, OpenJ9 runs a garbage collection cycle and releases free memory pages back to the operating system. The object heap is also compacted to make best use of the available memory for further application processing. For cloud services that charge based on memory usage, maintaining a small footprint can generate cost savings. For more information about tuning options that control this process, see <a href="../xxidletuningminidlewaittime/">-XX:IdleTuningMinIdleWaitTime</a>.</p>
<h3 id="cryptographic-operations">Cryptographic operations</h3>
<p>OpenJDK uses the in-built Java cryptographic implementation by default. However, native cryptographic implementations
typically provide better performance. OpenSSL is a native open source cryptographic toolkit for Transport Layer Security (TLS) and
Secure Sockets Layer (SSL) protocols, which is well established and used with many enterprise applications. The OpenSSL V1.0.x and V1.1.x implementations are currently supported for the Digest, CBC, GCM, and RSA algorithms. The OpenSSL V1.1.x implementation is also supported for the ChaCha20 and ChaCha20-Poly1305 algorithms.</p>
<p>On Linux and AIX platforms, the OpenSSL 1.0.x or 1.1.x library is expected to be found on the system path. If you use a package manager to install OpenSSL, the system path will be updated automatically. On other platforms, the OpenSSL 1.1.x library is currently bundled with the binaries from AdoptOpenJDK.</p>
<p>OpenSSL support is enabled by default for all supported algorithms. If you want to limit support to specific algorithms, a number of
system properties are available for tuning the implementation.</p>
<p>Each algorithm can be disabled individually by setting the following system properties on the command line:</p>
<ul>
<li>To turn off <strong>Digest</strong>, set <code>-Djdk.nativeDigest=false</code></li>
<li>To turn off <strong>ChaCha20</strong> and <strong>ChaCha20-Poly1305</strong>, set <code>-Djdk.nativeChaCha20=false</code>. <i class="fa fa-pencil-square-o" aria-hidden="true"></i> <strong>Note:</strong> <img alt="Start of content that applies to Java 8 (LTS)" src="../cr/java8.png" /> These algorithms are not supported on Java 8 <img alt="End of content that applies only to Java 8 (LTS)" src="../cr/java_close_lts.png" /></li>
<li>To turn off <strong>CBC</strong>, set <code>-Djdk.nativeCBC=false</code></li>
<li>To turn off <strong>GCM</strong>, set <code>-Djdk.nativeGCM=false</code></li>
<li>To turn off <strong>RSA</strong>, set <code>-Djdk.nativeRSA=false</code></li>
</ul>
<p>You can turn off all the algorithms by setting the following system property on the command line:</p>
<pre><code>-Djdk.nativeCrypto=false
</code></pre>

<p>To build a version of OpenJDK with OpenJ9 that includes OpenSSL support, follow the steps in our detailed build instructions:</p>
<ul>
<li><a href="https://github.com/eclipse/openj9/blob/master/doc/build-instructions/Build_Instructions_V8.md">OpenJDK 8 with OpenJ9</a>.</li>
<li><a href="https://github.com/eclipse/openj9/blob/master/doc/build-instructions/Build_Instructions_V11.md">OpenJDK 11 with OpenJ9</a>.</li>
<li><a href="https://github.com/eclipse/openj9/blob/master/doc/build-instructions/Build_Instructions_V13.md">OpenJDK 13 with OpenJ9</a>.</li>
</ul>
<p><i class="fa fa-pencil-square-o" aria-hidden="true"></i> <strong>Note:</strong> If you obtain an OpenJDK with OpenJ9 build from <a href="https://adoptopenjdk.net/">AdoptOpenJDK</a> that includes OpenSSL or build a version yourself that includes OpenSSL support, the following acknowledgements apply in accordance with the license terms:</p>
<ul>
<li><em>This product includes software developed by the OpenSSL Project for use in the OpenSSL Toolkit. (http://www.openssl.org/).</em></li>
<li><em>This product includes cryptographic software written by Eric Young (eay@cryptsoft.com).</em></li>
</ul>
<h3 id="exploiting-gpus">Exploiting GPUs</h3>
<p>OpenJ9 provides the <a href="https://www.ibm.com/support/knowledgecenter/SSYKE2_8.0.0/com.ibm.java.api.80.doc/com.ibm.cuda/index.html?view=kc">CUDA4J API</a> and the <a href="https://www.ibm.com/support/knowledgecenter/SSYKE2_8.0.0/com.ibm.java.api.80.doc/com.ibm.gpu/index.html?view=kc">com.ibm.gpu API</a>, which allow you to develop applications that can take advantage of graphics processing unit (GPU) processing for suitable functions, such as code page conversion. You can also enable the JIT compiler to offload certain processing tasks to a GPU by specifying the <code>-Xjit:enableGPU</code> option on the command line. When enabled, the JIT compiler determines when to offload tasks based on performance heuristics.</p>
<p>GPU processing is supported only on Windows (x86-64) and Linux (x86-64 and IBM Power LE) systems. For more information about enabling GPU processing, see <a href="https://www.ibm.com/support/knowledgecenter/SSYKE2_8.0.0/com.ibm.java.vm.80.doc/docs/gpu_overview.html">Exploiting graphics processing units</a>.</p>
<p>Special consideration is needed when using the WDDM driver model for GPUs on Windows. Using the WDDM driver model means the GPU is also used as a display device and as such is subject to the <a href="https://docs.microsoft.com/en-us/windows-hardware/drivers/display/timeout-detection-and-recovery">Timeout Detection and Recovery (TDR) mechanism</a> of Windows. If you are running demanding GPU workloads, you should increase the timeout from the default 2 seconds. More detail may be found in <a href="https://docs.nvidia.com/cuda/cuda-installation-guide-microsoft-windows/index.html#driver-model">NVIDIA's Installation Guide for Windows</a>.</p>
<h2 id="runtime-options">Runtime options</h2>
<p>Runtime options are specified on the command line and include system properties, standard options, nonstandard (<strong>-X</strong>) options, and <strong>-XX</strong> options. For a detailed list of runtime options, see <a href="../cmdline_specifying/">OpenJ9 command-line options</a></p>
<h2 id="default-settings">Default settings</h2>
<p>If you do not specify any options on the command line at run time, the OpenJ9 VM starts with default settings that define how it operates. For more information about these settings, see <a href="../openj9_defaults/">Default settings for the OpenJ9 VM</a>.</p>
<h2 id="using-jlink"><img alt="Start of content that applies to Java 11 (LTS) and later" src="../cr/java11plus.png" /> Using Jlink</h2>
<p>On Java 11 and later, you can use the <code>jlink</code> utility to create a custom OpenJ9 runtime image, which allows you to optimize image size.
If you do not require translations from the English language, the translation files can be removed to further optimize the size. You can achieve this by specifying the <code>--exclude-files=**java_**.properties</code> option when you run <code>jlink</code>. The default English <code>java.properties</code> file is unaffected.</p>
<h2 id="troubleshooting">Troubleshooting</h2>
<p>The OpenJ9 diagnostic component contains extensive features to assist with problem determination. Diagnostic data is produced under default conditions, but can also be controlled by starting the VM with the <a href="../xdump/">-Xdump option</a> or using the <code>com.ibm.jvm.Dump</code> API. You can also trace Java applications, methods, and VM operations by using the <a href="../xtrace/">-Xtrace option</a>.</p>
<p>To get started, read <a href="../diag_overview/">Diagnostic tools and data</a>.</p>
<!-- ==== END OF TOPIC ==== introduction.md ==== -->
                
                  
<!--
              
                
-->
              <!-- This block was originally in the theme's 'footer.html' partial file. It has been moved here in part to resolve issues with the footer being too large. -->
              
                <!--
* Copyright (c) 2017, 2018 IBM Corp. and others
*
* This program and the accompanying materials are made
* available under the terms of the Eclipse Public License 2.0
* which accompanies this distribution and is available at
* https://www.eclipse.org/legal/epl-2.0/ or the Apache
* License, Version 2.0 which accompanies this distribution and
* is available at https://www.apache.org/licenses/LICENSE-2.0.
*
* This Source Code may also be made available under the
* following Secondary Licenses when the conditions for such
* availability set forth in the Eclipse Public License, v. 2.0
* are satisfied: GNU General Public License, version 2 with
* the GNU Classpath Exception [1] and GNU General Public
* License, version 2 with the OpenJDK Assembly Exception [2].
*
* [1] https://www.gnu.org/software/classpath/license.html
* [2] http://openjdk.java.net/legal/assembly-exception.html
*
* SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH
* Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
-->
              
                <div class="md-footer-nav">
                  <nav class="md-footer-nav__inner md-grid">
<!-- Ignore all this to remove previous/next links in footer, but leave nav block else lose highlighting in LH navigation
                    <img alt="" src="../cr/rule.png"> [!-- Separator --]
                    
                      <a href="adoptopenjdk/" title="AdoptOpenJDK builds" class="md-flex md-footer-nav__link md-footer-nav__link--prev" rel="prev">
                        <div class="md-flex__cell md-flex__cell--shrink">
                          <i class="md-icon md-icon--arrow-back md-footer-nav__button"></i>
                        </div>
                        <div class="md-flex__cell md-flex__cell--stretch md-footer-nav__title">
                          <span class="md-flex__ellipsis">
                            <span class="md-footer-nav__direction">
                              Previous
                            </span>
                            AdoptOpenJDK builds
                          </span>
                        </div>
                      </a>
                    
                    
                      <a href="openj9_newuser/" title="New to OpenJ9?" class="md-flex md-footer-nav__link md-footer-nav__link--next" rel="next">
                        <div class="md-flex__cell md-flex__cell--stretch md-footer-nav__title">
                          <span class="md-flex__ellipsis">
                            <span class="md-footer-nav__direction">
                              Next
                            </span>
                            New to OpenJ9?
                          </span>
                        </div>
                        <div class="md-flex__cell md-flex__cell--shrink">
                          <i class="md-icon md-icon--arrow-forward md-footer-nav__button"></i>
                        </div>
                      </a>
                    
-->
                  </nav>
                </div>
              
              
            </article>
          </div>
        </div>
      </main>
      
        <!--
* Copyright (c) 2017, 2020 IBM Corp. and others
*
* This program and the accompanying materials are made
* available under the terms of the Eclipse Public License 2.0
* which accompanies this distribution and is available at
* https://www.eclipse.org/legal/epl-2.0/ or the Apache
* License, Version 2.0 which accompanies this distribution and
* is available at https://www.apache.org/licenses/LICENSE-2.0.
*
* This Source Code may also be made available under the
* following Secondary Licenses when the conditions for such
* availability set forth in the Eclipse Public License, v. 2.0
* are satisfied: GNU General Public License, version 2 with
* the GNU Classpath Exception [1] and GNU General Public
* License, version 2 with the OpenJDK Assembly Exception [2].
*
* [1] https://www.gnu.org/software/classpath/license.html
* [2] http://openjdk.java.net/legal/assembly-exception.html
*
* SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH
* Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
-->
<cite></cite>
<footer class="md-footer">

  <div class="md-footer-meta md-typeset">
    

      <!--
* Copyright (c) 2017, 2020 IBM Corp. and others
*
* This program and the accompanying materials are made
* available under the terms of the Eclipse Public License 2.0
* which accompanies this distribution and is available at
* https://www.eclipse.org/legal/epl-2.0/ or the Apache
* License, Version 2.0 which accompanies this distribution and
* is available at https://www.apache.org/licenses/LICENSE-2.0.
*
* This Source Code may also be made available under the
* following Secondary Licenses when the conditions for such
* availability set forth in the Eclipse Public License, v. 2.0
* are satisfied: GNU General Public License, version 2 with
* the GNU Classpath Exception [1] and GNU General Public
* License, version 2 with the OpenJDK Assembly Exception [2].
*
* [1] https://www.gnu.org/software/classpath/license.html
* [2] http://openjdk.java.net/legal/assembly-exception.html
*
* SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH
* Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
-->

  <div class="md-footer-social1">
    
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">
    
      <a href="https://github.com/eclipse/openj9" class="md-footer-social__link fa fa-github"></a>
    
      <a href="https://openj9.slack.com" class="md-footer-social__link fa fa-slack"></a>
    
      <a href="https://twitter.com/openj9" class="md-footer-social__link fa fa-twitter"></a>
    
      <a href="https://stackoverflow.com/search?q=OpenJ9" class="md-footer-social__link fa fa-stack-overflow"></a>
    
  </div>

    
    <div class="md-footer-eclipse1">OpenJ9 is an Eclipse Incubator project.</div>

    <div class="md-footer-links1">
      <span class="no-wrap"><i class="fa fa-chevron-circle-right f_mini" aria-hidden="true"></i><a class="dark-link" href="http://www.eclipse.org">Eclipse Foundation website</a></span>
      &nbsp; <span class="no-wrap"><i class="fa fa-chevron-circle-right f_mini" aria-hidden="true"></i><a class="dark-link" href="http://www.eclipse.org/legal/privacy.php">Privacy policy</a></span>
      &nbsp; <span class="no-wrap"><i class="fa fa-chevron-circle-right f_mini" aria-hidden="true"></i><a class="dark-link" href="http://www.eclipse.org/legal/termsofuse.php">Website terms of use</a></span>
      &nbsp; <span class="no-wrap"><i class="fa fa-chevron-circle-right f_mini" aria-hidden="true"></i><a class="dark-link" href="http://www.eclipse.org/legal/copyright.php">Copyright agent</a></span>
      &nbsp; <span class="no-wrap"><i class="fa fa-chevron-circle-right f_mini" aria-hidden="true"></i><a class="dark-link" href="http://www.eclipse.org/legal">Legal</a></span>
    </div>

    <div class="md-footer-power1">
      powered by
      <a href="http://www.mkdocs.org" title="MkDocs">MkDocs</a>
      and
      <a href="http://squidfunk.github.io/mkdocs-material/" title="Material for MkDocs">
      Material for MkDocs</a><br/><br/>
    </div>

  </div>

</footer>
      
    </div>
    
      <script src="../assets/javascripts/application.a8b5e56f.js"></script>
      
        
      <script>app.initialize({version:"1.0.4",url:{base:".."}})</script>
      
    
<script>
  window.ga = window.ga || function() {
    (ga.q = ga.q || []).push(arguments)
  }
  ga.l = +new Date
  /* Setup integration and send page view */
  ga("create", "UA-105616558-3", "mkdocs.org")
  ga("set", "anonymizeIp", true)
  ga("send", "pageview")
  /* Register handler to log search on blur */
  document.addEventListener("DOMContentLoaded", () => {
    if (document.forms.search) {
      var query = document.forms.search.query
      query.addEventListener("blur", function() {
        if (this.value) {
          var path = document.location.pathname;
          ga("send", "pageview", path + "?q=" + this.value)
        }
      })
    }
  })
</script>
<script async src="https://www.google-analytics.com/analytics.js"></script>
      
    
  </body>
</html>