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Alibaba Dragonwell 11 User Guide

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Jonathan Lu edited this page Dec 29, 2019 · 22 revisions

Introduction

Over the years, more than a billion lines of Java code have been written in Alibaba. While adopting OpenJDK to run these applications, we have found a need to customize it specifically for large-scale Java application deployments. Our customization has been well tested in our environment. We are now contributing some of our work into the Java community.

Alibaba Dragonwell, as a downstream version of OpenJDK, is the in-house OpenJDK implementation at Alibaba. It is optimized for online e-commerce, financial and logistics applications running on 100,000+ servers. Alibaba Dragonwell is the engine that runs these distributed Java applications in extreme scaling.

Alibaba Dragonwell is certified as compatible with the Java SE standard. The current release supports Linux/x86_64 platform only.

Alibaba Dragonwell is a "friendly fork" under the same licensing terms as the upstream OpenJDK project. Alibaba is committed to collaborate closely with the OpenJDK community. We intend to bring as many customized features as possible from Alibaba Dragonwell to the upstream.

Using Alibaba Dragonwell 11

Alibaba Dragonwell 11 JDK currently supports Linux/x86_64 platform only.

Installation

Two options to install Alibaba Dragonwell 11 are described below.

  • Option 1: Download and install pre-built Alibaba Dragonwell
  • Option 2: Install via YUM (Please stay tuned, will be available soon) Supports RedHat, CentOS, and AliOS only.
    • Add Aliyun's RPM repository to your /etc/repos.d/.
    • Install Alibaba Dragonwell using YUM: yum install dragonwell-11

Enable Alibaba Dragonwell for Java applications.

To enable Alibaba Dragonwell JDK for your application, simply set JAVA_HOME to point to the installation directory of Alibaba Dragonwell.

JFR Object Profiling

TODO

Serviceability

  1. Mini-Heapdump support With Alibaba Dragonwell you may dump partial Java heap by omitting the content of all primitive type arrays. A new option mini is added to the sub-command -dump of jmap tool. An example: jmap -dump:live,mini,format=b,file=heap121.bin <PID>

  2. -XX:ArrayAllocationWarningSize= The flag will print the calling stack of an array allocation if the allocation size is greater than the ArrayAllocationWarningSize. The default value is 512M, this flag could be enabled by jinfo:

// print the allocation stack if more than 1M array allocated.
jinfo -flag ArrayAllocationWarningSize=1048576 <pid>
// back to default value(512M)
jinfo -flag ArrayAllocationWarningSize=536870912 <pid>

Support

Please take a look at Alibaba Dragonwell FAQ for support. Or send mail to [email protected] for more help. Or you may scan QR code below with DingTalk to join the group chat.

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