OpenJDK

Set up JDK Mission Control with Red Hat Build of OpenJDK

Set up JDK Mission Control with Red Hat Build of OpenJDK

JDK Mission Control is now the newest member of the Red Hat Software Collections (RHSCL). JDK Mission Control is a powerful profiler for HotSpot Java virtual machines (JVMs) and has an advanced set of tools that enable efficient and detailed analysis of the extensive data collected by JDK Flight Recorder. The toolchain enables developers and administrators to collect and analyze data from Java applications running locally or deployed in production environments.

In this article, I will go through a primary example of setting up JDK Mission Control. For Linux, JDK Mission Control is part of the RHSCL and, for Windows, it is available as part of the OpenJDK zip distribution on the Red Hat Customer Portal.  For Linux, these instructions assume that Red Hat Build of OpenJDK 11 is already installed. I will show how to set up the system to install software from RHSCL, which provides the latest development technologies for Red Hat Enterprise Linux. Then, I will install the JDK Mission Control and run a simple sample application. The whole tutorial should take fewer than 10 minutes to complete.

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Creating and deploying a Java 8 runtime container image

Creating and deploying a Java 8 runtime container image

A Java runtime environment should be able to run compiled source code, whereas a development kit, for example, OpenJDK, would include all the libraries/binaries to compile and run the source code. Essentially the latter is a superset of the runtime environment. More details on OpenJDK support and lifecycle can be found here.

Red Hat ships and supports container images with OpenJDK for both Java 8 and 11. More details are here. If you are using Red Hat Middleware, the s2i images shipped are also useful to deploy, for example, on Red Hat Openshift Container Platform.

Note that Red Hat only provides OpenJDK-based Java 8 and 11 images. With that said, there will certainly be situations where developers would like to create their own Java runtime images. For example, there could be reasons such as minimizing storage to run a runtime image. On the other hand, a lot of manual work around libraries such as Jolokio or Hawkular and even security parameters would need to be set up as well. If you’d prefer not to get into those details, I would recommend using the container images for OpenJDK shipped by Red Hat.

In this article we will:

  • Build an image with Docker as well as Buildah.
  • We will run that image with Docker as well as Podman on localhost.
  • We will push our image to Quay.
  • Finally, we will run our app by importing a stream into OpenShift.

This article was written for both OpenShift 3.11 and 4.0 beta. Let’s jump right into it.

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Using Red Hat Application Migration Toolkit to see the impact of migrating to OpenJDK

Using Red Hat Application Migration Toolkit to see the impact of migrating to OpenJDK

Migrating from one software solution to another is a reality that all good software developers need to plan for. Having a plan helps to drive innovation at a continuous pace, whether you are developing software for in-house use or you are acquiring software from a vendor. In either case, never anticipating or planning for migration endangers the entire innovation value proposition. And in today’s ever-changing world of software, everyone who wants to benefit from the success of the cloud has to ensure that cloud innovation is continuous. Therefore, maintaining a stack that is changing along with technological advancements is a necessity.

In this article, we will take a look at the impact of moving to OpenJDK and the results will aid in drawing further conclusions and in planning. It’s quite common to be using a proprietary version of JDK, and this article addresses how to use Red Hat Application Migration Toolkit to analyze your codebase to understand the impact of migrating to OpenJDK.

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Migrating from Oracle JDK to OpenJDK on Red Hat Enterprise Linux: What you need to know

Migrating from Oracle JDK to OpenJDK on Red Hat Enterprise Linux: What you need to know

Oracle has announced that the Oracle JDK 8 builds released after Jan 2019 cease to be free for commercial use. GPL + Classpath Exception licensed (free for any use, subject to that license) are current made available by Oracle through http://jdk.java.net/11/. (See also Oracle’s blog entry & licensing).
An alternative is to use OpenJDK and effort is underway to make them fully interchangeable. A number of companies who are currently using Oracle JDK in production are making the decision to switch to OpenJDK or have already done so.

Andrew Haley (Red Hat’s Java Platform Lead Engineer) recently wrote a great article on the direction of OpenJDK.

In this article, I’ll discuss: the technical and support implications of the migration, what developers and operations teams need to know, and solutions to potential challenges.

I’ll go over the Red Hat support model and technical details of how to install, update, and run different OpenJDK versions on Red Hat Enterprise Linux (RHEL) 6 and 7 systems. I’ll also discuss the operations of Java applications (such as Red Hat JBoss Enterprise Application Platform (JBoss EAP) and other servers) on top of OpenJDK.

While this article is about OpenJDK on RHEL, I should also point out that OpenJDK for Windows can also be downloaded from developers.redhat.com. This lets you use the same JDK for Linux and Windows.

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The future of Java and OpenJDK updates without Oracle support

The future of Java and OpenJDK updates without Oracle support

Oracle recently announced that it would no longer supply free (as in beer) binary downloads for JDK releases after a six-month period, and neither would Oracle engineers write patches for OpenJDK bugs after that period. This has caused a great deal of concern among some Java users.

From my point of view, this is little more than business as usual. Several years ago, the OpenJDK 6 updates (jdk6u) project was relinquished by Oracle and I assumed leadership, and then the same happened with OpenJDK 7. Subsequently, Andrew Brygin of Azul took over the leadership of OpenJDK 6. The OpenJDK Vulnerability Group, with members from many organizations, collaborates on critical security issues. With the help of the wider OpenJDK community and my team at Red Hat, we have continued to provide updates for critical bugs and security vulnerabilities at regular intervals. I can see no reason why this process should not work in the same way for OpenJDK 8 and the next long-term support release, OpenJDK 11.

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Red Hat Releases New Development Tools

Red Hat Releases New Development Tools

I’m extremely pleased to announce the latest releases of our Red Hat developer tools, available on multiple platforms. The general theme of this release is expanded usability, product integration, expanded support for Middleware products in Development Suite, plus the brand new addition of Kompose and the DevTools channel for Red Hat Enterprise Linux.

This collection of tools has been assembled into an easy-to-use installer to help software developers quickly and easily put together a development environment to create containerized enterprise Java apps by installing OpenShift on their desktop. The Developer Tools Installer will automatically download, install and configure the selected tools on macOS, Windows and Red Hat Enterprise Linux.  Development Suite also simplifies the installation and configuration of EAP, Fuse, and Kompose. As always, it’s available at no-cost from developers.redhat.com/downloads.

Today, Red Hat has released new versions of the following:

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OpenJDK and Containers

What can be done to help the OpenJDK JVM play well in the world of Linux Containers?
I thought I’d start tackling this issue by answering some frequently asked questions:

Why is it when I specify -Xmx=1g my JVM uses up more memory than 1gb of memory?

Specifying -Xmx=1g is telling the JVM to allocate a 1gb heap. It’s not telling the JVM to limit its entire memory usage to 1gb. There are card tables, code caches, and all sorts of other off heap data structures. The parameter you use to specify total memory usage is -XX:MaxRAM. Be aware that with -XX:MaxRam=500m your heap will be approximately 250mb.

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Preparing CentOS 6.8 for Work

Preparing CentOS 6.8 for Work

I came across Linux in 2005, it was Debian. Then followed a love affair with Ubuntu, for which in March 2009 I purchased a netbook Asus EeePC 1000. In 2010, I began to contribute to ALT Linux participating in the “School Project” and even became a basic256 package maintainer.

The last few years my EeePC with Ubuntu peacefully rested deep in my cupboard. Then there was a chance to clean off the dust. There was a task to get acquainted with CentOS Linux and test examples for my webinar “Apache Ant – quick start”.

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