<!--
* 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/version0.18/">
      
      
        <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>Version 0.18.1 -  </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="../#whats-new-in-version-0181" 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/" 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">
    eclipse/openj9
  </div>
</a>
            </div>
          </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/" 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">
    eclipse/openj9
  </div>
</a>
    </div>
  
  <ul class="md-nav__list" data-md-scrollfix>
    
      
  <li class="md-nav__item">
    <a href=".." title="About the docs" class="md-nav__link">
      About the docs
    </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">
    <a href="../introduction/" title="Getting started" class="md-nav__link">
      Getting started
    </a>
  </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--active md-nav__item--nested">
    
      <input class="md-toggle md-nav__toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5" checked>
    
    <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="../version0.21/" title="Version 0.21.0" class="md-nav__link">
      Version 0.21.0
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../version0.20/" title="Version 0.20.0" class="md-nav__link">
      Version 0.20.0
    </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 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">
        Version 0.18.1
      </label>
    
    <a href="./" title="Version 0.18.1" class="md-nav__link md-nav__link--active">
      Version 0.18.1
    </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="#features-and-changes" class="md-nav__link">
    Features and changes
  </a>
  
    <nav class="md-nav">
      <ul class="md-nav__list">
        
          <li class="md-nav__item">
  <a href="#binaries-and-supported-environments" class="md-nav__link">
    Binaries and supported environments
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#technical-preview-of-jitserver-technology" class="md-nav__link">
    Technical preview of JITServer technology
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#jextract-now-available-on-macos-for-openjdk-version-8" class="md-nav__link">
    jextract now available on macOS for OpenJDK version 8
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#new-shared-classes-cache-suboption-to-turn-off-timestamp-checking" class="md-nav__link">
    New shared-classes cache suboption to turn off timestamp checking
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#removal-of-restriction-on-layered-shared-cache" class="md-nav__link">
    Removal of restriction on layered shared cache
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#-xmso-1-mb-minimum-value-on-zos-64-bit" class="md-nav__link">
    -Xmso 1 MB minimum value on z/OS 64-bit
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#jstat-new-java-statistics-monitoring-tool" class="md-nav__link">
    jstat: new Java statistics monitoring tool
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#-xxtransparenthugepage-is-enabled-by-default-on-more-linux-systems" class="md-nav__link">
    -XX:+TransparentHugePage is enabled by default on more Linux systems
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#new-exit-dump-agent-and-exitonoutofmemoryerror-option" class="md-nav__link">
    New exit dump agent and ExitOnOutOfMemoryError option
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#ludcl-caching-enabled-by-default" class="md-nav__link">
    LUDCL caching enabled by default
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#terabytes-suffix-support-for-x-and-xx-options-that-take-a-size" class="md-nav__link">
    Terabytes suffix support for -X and -XX options that take a size
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#improved-support-for-pause-less-garbage-collection" class="md-nav__link">
    Improved support for pause-less garbage collection
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#-xgcnoconcurrentscavenge-option" class="md-nav__link">
    -Xgc:noConcurrentScavenge option
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#support-for-openjdk-hotspot-options" class="md-nav__link">
    Support for OpenJDK HotSpot options
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#shared-classes-cache-suboptions-for-layered-caches-no-longer-experimental" class="md-nav__link">
    Shared classes cache suboptions for layered caches no longer experimental
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#-djavalangstringsubstringnocopy-option" class="md-nav__link">
    -Djava.lang.string.substring.nocopy option
  </a>
  
</li>
        
      </ul>
    </nav>
  
</li>
      
        <li class="md-nav__item">
  <a href="#full-release-information" class="md-nav__link">
    Full release information
  </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-5-6" type="checkbox" id="nav-5-6">
    
    <label class="md-nav__link" for="nav-5-6">
      Earlier releases
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="2">
      <label class="md-nav__title" for="nav-5-6">
        Earlier releases
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <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">
    <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 md-nav__item--nested">
    
      <input class="md-toggle md-nav__toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6">
    
    <label class="md-nav__link" for="nav-6">
      Memory management
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="1">
      <label class="md-nav__title" for="nav-6">
        Memory management
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <li class="md-nav__item">
    <a href="../allocator/" title="Memory allocation" class="md-nav__link">
      Memory allocation
    </a>
  </li>

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

        
      </ul>
    </nav>
  </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="../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="../xxgloballockreservation/" title="-XX:[+|-]GlobalLockReservation" class="md-nav__link">
      -XX:[+|-]GlobalLockReservation
    </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="../xxhandlesigabrt/" title="-XX:[+|-]HandleSIGABRT" class="md-nav__link">
      -XX:[+|-]HandleSIGABRT
    </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="../xxoriginaljdk8heapsizecompatibilitymode/" title="-XX:[+|-]OriginalJDK8HeapSizeCompatibilityMode" class="md-nav__link">
      -XX:[+|-]OriginalJDK8HeapSizeCompatibilityMode
    </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="../xxprintflagsfinal/" title="-XX:[+|-]PrintFlagsFinal" class="md-nav__link">
      -XX:[+|-]PrintFlagsFinal
    </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 md-nav__item--nested">
    
      <input class="md-toggle md-nav__toggle" data-md-toggle="nav-14" type="checkbox" id="nav-14">
    
    <label class="md-nav__link" for="nav-14">
      API documentation
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="1">
      <label class="md-nav__title" for="nav-14">
        API documentation
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <li class="md-nav__item">
    <a href="../api-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-14-2" type="checkbox" id="nav-14-2">
    
    <label class="md-nav__link" for="nav-14-2">
      Java 8 API
    </label>
    <nav class="md-nav" data-md-component="collapsible" data-md-level="2">
      <label class="md-nav__title" for="nav-14-2">
        Java 8 API
      </label>
      <ul class="md-nav__list" data-md-scrollfix>
        
        
  <li class="md-nav__item">
    <a href="../api-conditionhandling/" title="Condition exception handling" class="md-nav__link">
      Condition exception handling
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../api-cuda/" title="CUDA4J" class="md-nav__link">
      CUDA4J
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../api-daa/" title="Data access acceleration" class="md-nav__link">
      Data access acceleration
    </a>
  </li>

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

        
  <li class="md-nav__item">
    <a href="../api-gpu/" title="GPU" class="md-nav__link">
      GPU
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../api-jvm/" title="JVM diagnostic utilities" class="md-nav__link">
      JVM diagnostic utilities
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../api-langmgmt/" title="Monitoring and management" class="md-nav__link">
      Monitoring and management
    </a>
  </li>

        
  <li class="md-nav__item">
    <a href="../api-shrc/" title="Shared classes" class="md-nav__link">
      Shared classes
    </a>
  </li>

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

        
  <li class="md-nav__item">
    <a href="../api-jdk11/" title="Java 11 API" class="md-nav__link">
      Java 11 API
    </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="#features-and-changes" class="md-nav__link">
    Features and changes
  </a>
  
    <nav class="md-nav">
      <ul class="md-nav__list">
        
          <li class="md-nav__item">
  <a href="#binaries-and-supported-environments" class="md-nav__link">
    Binaries and supported environments
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#technical-preview-of-jitserver-technology" class="md-nav__link">
    Technical preview of JITServer technology
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#jextract-now-available-on-macos-for-openjdk-version-8" class="md-nav__link">
    jextract now available on macOS for OpenJDK version 8
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#new-shared-classes-cache-suboption-to-turn-off-timestamp-checking" class="md-nav__link">
    New shared-classes cache suboption to turn off timestamp checking
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#removal-of-restriction-on-layered-shared-cache" class="md-nav__link">
    Removal of restriction on layered shared cache
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#-xmso-1-mb-minimum-value-on-zos-64-bit" class="md-nav__link">
    -Xmso 1 MB minimum value on z/OS 64-bit
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#jstat-new-java-statistics-monitoring-tool" class="md-nav__link">
    jstat: new Java statistics monitoring tool
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#-xxtransparenthugepage-is-enabled-by-default-on-more-linux-systems" class="md-nav__link">
    -XX:+TransparentHugePage is enabled by default on more Linux systems
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#new-exit-dump-agent-and-exitonoutofmemoryerror-option" class="md-nav__link">
    New exit dump agent and ExitOnOutOfMemoryError option
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#ludcl-caching-enabled-by-default" class="md-nav__link">
    LUDCL caching enabled by default
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#terabytes-suffix-support-for-x-and-xx-options-that-take-a-size" class="md-nav__link">
    Terabytes suffix support for -X and -XX options that take a size
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#improved-support-for-pause-less-garbage-collection" class="md-nav__link">
    Improved support for pause-less garbage collection
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#-xgcnoconcurrentscavenge-option" class="md-nav__link">
    -Xgc:noConcurrentScavenge option
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#support-for-openjdk-hotspot-options" class="md-nav__link">
    Support for OpenJDK HotSpot options
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#shared-classes-cache-suboptions-for-layered-caches-no-longer-experimental" class="md-nav__link">
    Shared classes cache suboptions for layered caches no longer experimental
  </a>
  
</li>
        
          <li class="md-nav__item">
  <a href="#-djavalangstringsubstringnocopy-option" class="md-nav__link">
    -Djava.lang.string.substring.nocopy option
  </a>
  
</li>
        
      </ul>
    </nav>
  
</li>
      
        <li class="md-nav__item">
  <a href="#full-release-information" class="md-nav__link">
    Full release information
  </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/edit/master/docs/version0.18.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="whats-new-in-version-0181">What's new in version 0.18.1</h1>
<p>The following new features and notable changes since v 0.17.0 are included in this release:</p>
<ul>
<li><a href="#binaries-and-supported-environments">Binaries and supported environments</a></li>
<li><a href="#technical-preview-of-jitserver-technology">Technical preview of JITServer technology</a></li>
<li><a href="#jextract-now-available-on-macos-for-openjdk-version-8"><code>jextract</code> now available on macOS&reg; for OpenJDK version 8</a></li>
<li><a href="#new-shared-classes-cache-suboption-to-turn-off-timestamp-checking">New shared-classes cache suboption to turn off timestamp checking</a></li>
<li><a href="#removal-of-restriction-on-layered-shared-cache">Removal of restriction on layered shared cache</a></li>
<li><a href="#-xmso-1-mb-minimum-value-on-zos-64-bit"><code>-Xmso</code> 1 MB minimum value on z/OS&reg; 64-bit</a></li>
<li><a href="#jstat-new-java-statistics-monitoring-tool"><code>jstat</code>: new Java&trade; statistics monitoring tool</a></li>
<li><a href="#-xxtransparenthugepage-is-enabled-by-default-on-more-linux-systems"><code>-XX:+TransparentHugePage</code> is enabled by default on more Linux&reg; systems</a></li>
<li><a href="#new-exit-dump-agent-and-exitonoutofmemoryerror-option">New exit dump agent and <code>ExitOnOutOfMemoryError</code> option</a></li>
<li><a href="#ludcl-caching-enabled-by-default">LUDCL caching enabled by default</a></li>
<li><a href="#terabytes-suffix-support-for-x-and-xx-options-that-take-a-size">Terabytes suffix support for <code>-X</code> and <code>-XX</code> options that take a size</a></li>
<li><a href="#improved-support-for-pause-less-garbage-collection">Improved support for pause-less garbage collection</a></li>
<li><a href="#-xgcnoconcurrentscavenge-option"><code>-Xgc:noConcurrentScavenge</code> option</a></li>
<li><a href="#support-for-openjdk-hotspot-options">Support for OpenJDK HotSpot options</a></li>
<li><a href="#shared-classes-cache-suboptions-for-layered-caches-no-longer-experimental">Shared classes cache suboptions for layered caches no longer experimental</a></li>
<li><a href="#-djavalangstringsubstringnocopy-option"><code>-Djava.lang.string.substring.nocopy</code> option</a></li>
</ul>
<h2 id="features-and-changes">Features and changes</h2>
<h3 id="binaries-and-supported-environments">Binaries and supported environments</h3>
<p>OpenJ9 releases 0.18.0 and 0.18.1 support OpenJDK 8, 11, and 13. Binaries are available from the AdoptOpenJDK community at the following links:</p>
<ul>
<li><a href="https://adoptopenjdk.net/archive.html?variant=openjdk8&amp;jvmVariant=openj9">OpenJDK version 8</a></li>
<li><a href="https://adoptopenjdk.net/archive.html?variant=openjdk11&amp;jvmVariant=openj9">OpenJDK version 11</a></li>
<li><a href="https://adoptopenjdk.net/archive.html?variant=openjdk13&amp;jvmVariant=openj9">OpenJDK version 13</a></li>
</ul>
<p><i class="fa fa-pencil-square-o" aria-hidden="true"></i> <strong>Note:</strong> Binaries at AdoptOpenJDK that are labeled 0.18.1 include additional bug fixes. For more information, see the <a href="https://github.com/eclipse/openj9/blob/master/doc/release-notes/0.18/0.18.md">release notes</a>.</p>
<p>To learn more about support for OpenJ9 releases, including OpenJDK levels and platform support, see <a href="../openj9_support/">Supported environments</a>.</p>
<h3 id="technical-preview-of-jitserver-technology">Technical preview of JITServer technology</h3>
<p>A technical preview of JITServer technology is included in this release. It's currently available for OpenJDK 8 and OpenJDK 11 running on Linux on x86-64.</p>
<p>JITServer technology decouples the JIT compiler from the VM and lets the JIT compiler run remotely in its own process. This mechanism prevents your Java application suffering possible negative effects due to CPU and memory consumption caused by JIT compilation. This technology can improve quality of service, robustness, and even performance of Java applications. For more information, see <a href="../jitserver/">JITServer technology</a>.</p>
<h3 id="jextract-now-available-on-macos-for-openjdk-version-8"><code>jextract</code> now available on macOS for OpenJDK version 8</h3>
<p>The <a href="../tool_jextract/"><code>jextract</code> tool</a> is now available on macOS platforms (as well as AIX&reg; and Linux) for <em>all</em> current versions of OpenJDK: 8, 11, and 13.</p>
<h3 id="new-shared-classes-cache-suboption-to-turn-off-timestamp-checking">New shared-classes cache suboption to turn off timestamp checking</h3>
<p>You can set the <code>-Xshareclasses:noTimestampChecks</code> option to turn off timestamp checking in shared classes. For more information, see the <a href="../xshareclasses/#notimestampchecks">-Xshareclasses:noTimestampChecks</a> option.</p>
<h3 id="removal-of-restriction-on-layered-shared-cache">Removal of restriction on layered shared cache</h3>
<p>In the previous release, there is a restriction that the <a href="../interface_jvmti/#jvmtisharedcacheinfo-structure"><code>jvmtiSharedCacheInfo.isCorrupt</code></a> field and the <code>SharedClassCacheInfo.isCacheCorrupt()</code> method cannot detect a corrupted cache that has a layer number other than <code>0</code>. This restriction is now removed. See the <a href="../api-shrc/">Shared classes API documentation</a>. <!-- Link to API --></p>
<h3 id="-xmso-1-mb-minimum-value-on-zos-64-bit"><code>-Xmso</code> 1 MB minimum value on z/OS 64-bit</h3>
<p>On z/OS 64-bit, <a href="../xmso/"><code>-Xmso</code></a> has a 1 MB minimum value, to match the minimum stack space provided by the operating system. If you set a value smaller than 1 MB, the value is ignored.</p>
<h3 id="jstat-new-java-statistics-monitoring-tool"><code>jstat</code>: new Java statistics monitoring tool</h3>
<p>For compatibility with the HotSpot implementation, OpenJ9 now includes an independent implementation of the <code>jstat</code> tool for retrieving statistics on a VM. For more information, see <a href="../tool_jstat/">Java statistics monitoring tool</a>.</p>
<h3 id="-xxtransparenthugepage-is-enabled-by-default-on-more-linux-systems"><code>-XX:+TransparentHugePage</code> is enabled by default on more Linux systems</h3>
<p><a href="../xxtransparenthugepage/">-XX:+TransparentHugePage</a> is enabled by default on Linux systems for POWER&reg; and IBM Z&reg; as well as x86 systems. This option takes affect only when Transparent Huge Pages (THP) is set to <code>madvise</code> on your system. When Transparent Huge Pages are used, your application footprint might increase.</p>
<h3 id="new-exit-dump-agent-and-exitonoutofmemoryerror-option">New exit dump agent and <code>ExitOnOutOfMemoryError</code> option</h3>
<p>The new exit dump agent shuts down the VM when the specified event occurs. The exit agent is at priority level 0 and the tool agent has been moved to priority level 1 to aid in mimicking the behavior of HotSpot options. For more information about dump agents, see <a href="../xdump/#dump-agents"><code>-Xdump</code></a>.</p>
<p>OpenJ9 now supports the HotSpot option <a href="../xxexitonoutofmemoryerror/"><code>-XX:[+|-]ExitOnOutOfMemoryError</code></a>. You can set this option to have the VM shut down when a <code>java.lang.OutOfMemory</code> error is thrown by the VM or in Java code. The exit dump agent is used in the implementation of <code>-XX:[+|-]ExitOnOutOfMemoryError</code>.</p>
<h3 id="ludcl-caching-enabled-by-default">LUDCL caching enabled by default</h3>
<p>By caching the Latest User Defined Class Loader (LUDCL), Java applications that use deserialization extensively can see a performance improvement. This capability is controlled by the <a href="../dcomibmenableclasscaching/"><code>-Dcom.ibm.enableClassCaching</code></a> system property and is now enabled by default. This feature was disabled for the 0.17.0 release due to <a href="https://github.com/eclipse/openj9/issues/7332">issue #7332</a> which has now been resolved.</p>
<h3 id="terabytes-suffix-support-for-x-and-xx-options-that-take-a-size">Terabytes suffix support for <code>-X</code> and <code>-XX</code> options that take a size</h3>
<p>OpenJ9 now supports 't' and 'T' suffixes (indicating terabytes) for <code>-X</code> and <code>-XX</code> options that take a <code>&lt;size&gt;</code> parameter.</p>
<h3 id="improved-support-for-pause-less-garbage-collection">Improved support for pause-less garbage collection</h3>
<p>Support for Concurrent scavenge mode is now extended to macOS. For more information, see <a href="../xgc/#concurrentscavenge"><code>-Xgc:concurrentScavenge</code></a>.</p>
<h3 id="-xgcnoconcurrentscavenge-option"><code>-Xgc:noConcurrentScavenge</code> option</h3>
<p>The previously undocumented option <a href="../xgc/#noconcurrentscavenge"><code>-Xgc:noConcurrentScavenge</code></a> disables pause-less garbage collection.</p>
<h3 id="support-for-openjdk-hotspot-options">Support for OpenJDK HotSpot options</h3>
<p>For compatibility, the following OpenJDK HotSpot options are now supported by OpenJ9:</p>
<ul>
<li><a href="../xxparallelgcthreads/">-XX:ParallelGCThreads</a></li>
<li><a href="../xxconcgcthreads/">-XX:ConcGCThreads</a></li>
<li><a href="../xxparallelcmsthreads/">-XX:ParallelCMSThreads</a></li>
</ul>
<h3 id="shared-classes-cache-suboptions-for-layered-caches-no-longer-experimental">Shared classes cache suboptions for layered caches no longer experimental</h3>
<p>The suboptions for creating layered caches are no longer marked experimental.</p>
<p>The new options are:</p>
<ul>
<li><a href="../xshareclasses/#createlayer"><code>createLayer</code></a></li>
<li><a href="../xshareclasses/#layer"><code>layer=&lt;number&gt;</code></a> (see this section for more information about layered caches)</li>
<li><a href="../xshareclasses/#printtoplayerstats-cache-utility"><code>printTopLayerStats</code></a></li>
<li><a href="../xshareclasses/#destroyalllayers"><code>destroyAllLayers</code></a></li>
</ul>
<h3 id="-djavalangstringsubstringnocopy-option"><code>-Djava.lang.string.substring.nocopy</code> option</h3>
<p>The previously undocumented Java 8 option <a href="../djavalangstringsubstringnocopy/"><code>-Djava.lang.string.substring.nocopy=true</code></a> avoids String sharing by String.substring(), which is the same behavior as the Oracle HotSpot VM.</p>
<h2 id="full-release-information">Full release information</h2>
<p>To see a complete list of changes between Eclipse OpenJ9 v 0.17.0 and v 0.18.0 releases, see the <a href="https://github.com/eclipse/openj9/blob/master/doc/release-notes/0.18/0.18.md">Release notes</a>.</p>
<!-- ==== END OF TOPIC ==== version0.18.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. -->
            </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="footer">
  <div class="md-footer-meta">
    

    <div class="above-line">
      <div class="above-line-links">
        <div class="column">
          <h3 >Docs</h3>
          <span class="footer-link"><a href="/openj9_newuser/" >New to OpenJ9?</a></span>
          <span class="footer-link"><a href="/introduction/">Getting started</a></span>
          <span class="footer-link"><a href="/cmdline_specifying/">Command-line options</a></span>
        </div>
  
        <div class="column">
          <h3>Resources</h3>
          <span class="footer-link"><a href="https://www.eclipse.org/openj9/about/" rel="noopener noreferrer" target="_blank">About</a></span>
          <span class="footer-link"><a href="https://www.eclipse.org/openj9/performance/" rel="noopener noreferrer" target="_blank">Performance</a></span>
        </div>
  
        <div class="column">
          <h3 >Community</h3>
          <span class="footer-link"><a href="https://www.eclipse.org/openj9/news/" rel="noopener noreferrer" target="_blank">News</a></span>
          <span class="footer-link"><a href="https://blog.openj9.org/" rel="noopener noreferrer" target="_blank">Blogs</a></span>
        </div>
      </div>

      <div class="column-incubator">
        <div class="arrange-column">
          <h3 ><b>OpenJ9 is an Eclipse Incubator project</b></h3>
          <a class="incubator-image" href="http://wiki.eclipse.org/Development_Resources/Process_Guidelines/What_is_Incubation" target="_blank"><img width="50px" src="../cr/incubator-logo.svg" alt="Eclipse Incubation"></a>
        </div>
      </div>
    </div>

    <div class="horizontal-line"></div>

    <div class="below-line">
      <span class="below-line-links"><a href="https://www.eclipse.org/" rel="noopener noreferrer" target="_blank">Eclipse Foundation Website </a></span>
      <span class="below-line-links"><a href="https://www.eclipse.org/legal/privacy.php" rel="noopener noreferrer" target="_blank">Privacy Policy</a></span>
      <span class="below-line-links"><a href="https://www.eclipse.org/legal/termsofuse.php" rel="noopener noreferrer" target="_blank">Terms of Use</a></span>
      <span class="below-line-links"><a href="https://www.eclipse.org/legal/copyright.php" rel="noopener noreferrer" target="_blank">Copyright Agent</a></span>
      <span class="below-line-links"><a href="https://www.eclipse.org/legal/" rel="noopener noreferrer" target="_blank">Legal</a></span>
      <div class="below-line-social-media-icons">
        <span class="social-media-link"> <a href="https://twitter.com/openj9/" rel="noopener noreferrer" target="_blank"> <img src="../cr/twitter-logo.svg" alt="Twitter Logo"></img></a></span>
        <span class="social-media-link"> <a href="https://github.com/eclipse/openj9" rel="noopener noreferrer" target="_blank"> <img src="../cr/github-logo.svg" alt="GitHub Logo"></img></a></span>
        <span class="social-media-link"> <a href="https://openj9.slack.com/" rel="noopener noreferrer" target="_blank"><img src="../cr/slack-icon.svg" alt="Slack logo"></img></a></span>
        <span class="social-media-link"> <a href="https://stackoverflow.com/search?q=%23OpenJ9" rel="noopener noreferrer" target="_blank"><img src="../cr/stackoverflow-logo.svg" alt="Stack Overflow logo"></img></a></span>
      </div>
    </div>  
  </div>
</footer>
      
    </div>
    
      <script src="../assets/javascripts/application.a8b5e56f.js"></script>
      
        
      <script>app.initialize({version:"1.0.4",url:{base:".."}})</script>
      
        <script src="../javascripts/oj9.js"></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>