Leo Ufimtsev

Leo Ufimtsev

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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

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By Leo Ufimtsev

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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How to manually copy SSH public keys to servers on Red Hat Enterprise Linux

How to manually copy SSH public keys to servers on Red Hat Enterprise Linux

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By Leo Ufimtsev

We often use ssh-copy-id to copy ssh keys from our local Linux computers to RHEL servers in order to connect without typing in a password. This is not only for convenience; it enables you to script and automate tasks that involve remote machines.  Also, using ssh keys correctly is considered a best practice.  If you are conditioned to respond with your password every time you are prompted, you might not notice a prompt that isn’t legitimate (for example, spoofed).

What about when you can’t use ssh-copy-id or the target user ID doesn’t have a password (for example, an Ansible service user)? This article explains how to do it manually and avoid the common pitfall of forgetting to set the proper permissions.

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Eclipse for JNI development and debugging on Linux (Java and C)

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By Leo Ufimtsev

selection_166Cross language development in one project

In this tutorial style article I’ll discuss how to configure Eclipse for Java Native Interface (JNI) development based on a sample project that you can copy and modify. I.e, you can have a single project that can be both Java and C at the same time, and support a full code navigation and debugging of both languages.

This article is focused on the configuration of Eclipse rather than explaining JNI itself, however there are links to JNI literature at the end.

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The Eclipse Developer’s guide to Clean Code (part 1)

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By Leo Ufimtsev

Front_pic“Even bad code can function. But if code isn’t clean, it can bring a development organization to its knees”  — Clean Code

We spent 10 times more time reading code than writing it. Thus keeping code clean is essential for maintainability and company growth, but doing it by hand can be tedious.

Let’s take a look at some of the clean code practices and how we can use Eclipse to re-factor code faster.

Continue reading “The Eclipse Developer’s guide to Clean Code (part 1)”

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