In order to avoid legal problems with Oracle (which owns proprietary extensions), camore and more companies are building their own JDK from OpenJDK and benefit the community with their work.
Be it Red Hat, Amazon among others, to name a few, all of these companies have their own JDKs. According to them, Oracle's proprietary extensions destroy the confidence of developers who are gradually moving away from the Java language.
Alibaba dragonwell
Java is a widely used language on Alibaba as it needed an optimized JDK for its applications e-commerce, finance, and online logistics services running on more than 100,000 servers.
From this need arose Alibaba Dragonwell, a JDK derived from OpenJDK and which is the engine that runs Alibaba's distributed Java applications at extreme scales, in accordance with the company's terms.
As a fork of OpenJDK, Alibaba Dragonwell JDK is free software under the GNU 2.0 license, available on GitHub.
Alibaba Group engineers recently introduced your own JDK implementation on GitHub. For the company, this implementation was born out of the need to find a Java resource that is well suited to its applications and enables its large-scale implementation.
This internal customization or downstream version of OpenJDK from Alibaba Group has been named Alibaba Dragon Well 8.0. As expected, this customization has been implemented for specific business needs.
At the Dragonwell team presentation:
It is noted that the latter is optimized for online e-commerce, finance and logistics applications and already works on more than one hundred thousand servers. »
Alibaba Dragonwell is the engine that runs our distributed Java applications with extreme scalability, ”said the team.
The Alibaba Dragonwell team reports that the latter is certified as compliant with the Java SE standard and that the current version is only compatible with the Linux platform for x86 and x64 architectures.
Besides being a fork of OpenJDK, it has other features that the company considers very essential to its work.
"By adopting OpenJDK to run our applications, we realized the need to customize it specifically for large-scale Java application deployments," the team wrote.
About Alibaba Dragonwell 8.0 New Version
The new version of Alibaba Dragonwell it has a new garbage collector called CMS, a flight recorder (JFR) and brings new additions.
On the report of this new release from Alibaba Dragonwell, the development team highlights that:
- A new mini-option is added to the dump subcommand of the dump tool to ignore the contents of the primitive arrays of heapdump.
- As well as a new PrintYoungGenHistoAfterParNewGC option to print the object histogram after a ParNew GC.
- The PrintGCRootsTraceTime option was added to print the ParNew GC details as G1GC. Help users to find the problem of long rest time. Can be opened / closed by jinfo
And a new ArrayAllocationWarningSize option to print the call stack of an array mapping that exceeds ArrayAllocationWarningSize. The default value for this option is 512M. This can be changed by jinfo.
How to get Alibaba Dragonwell 8.0?
This JDK is available for those enthusiasts who want to know a little more about it or implement it on their servers.
It is important to mention that Alibaba Dragonwell JDK only supports Linux platform on x86 and x64 architectures at the moment.
For RHEL, CentOS and AliOS systems can be added the following repository.
In the case of CentOS this we add it with:
curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
And we install with:
sudo yum install dragonwell-8
Now just to enable Alibaba Dragonwell JDK for your application, ofPlease configure JAVA_HOME to point to the Alibaba Dragonwell installation directory.
For other systems you must download the JDK from Github, the link is this.
You can consult the Alibaba Dragonwell 8.0 implementation instructions as well as more information about it. In the following link.