Great programs like the file hosting downloader JDownloader or the feed reader RSSOwl require Java to run. That's fine if you have full control of a system, and not so great if you sometimes have to work on a system where Java, in the form of the Java Runtime Environment (JRE) is not installed. If you want to take your apps with you, you need to find a way to get them to run on the system despite that.
The answer is jPortable, a portable Java Runtime Environment that is provided by Portable Apps. While designed for use with portable programs offered by the site and service, it is not restricted to that.
First thing you need to do is download the installer from the Portable Apps website. Please note that this is a web installer, which means that the installer will download files from the Internet during installation.The whole package has a size of roughly 38 Megabytes. The installation basically moves all files into a folder that you have selected before. This can be an USB drive or stick, or an internal hard drive for instance.
The portable version of Java is installed in \PortableApps\CommonFiles\Java by default, and recognized automatically by other programs of the Portable Apps suite. You can however use it as well for programs that are not part of the suite. Let me show you how you can get RSSOwl working with a portable version of Java.
Once you have installed both the portable Java version and RSSOwl, you need to copy the Java directory into the RSSOwl directory. Once it is there, rename the Java folder to jre, and start RSSOwl. You will notice that it will start up just fine, even with no Java installed on the system.
There is a second option available, which works if you can modify the system paths. Use the Windows-Pause shortcut to bring up the System control panel applet. Click on Advanced system settings there, and locate Environmental Variables in the window that opens up. (this is the way it is done under Windows 7)
Here you find user and system variables. Find path under System, select it, and click on Edit to modify it. Simply append a ; followed by the full Java portable directory path to it, and click on ok afterwards to save the new setting. If you prefer a better editor interface, try Redmond Path instead.
You can also use the command line to start Java programs from there.
Having access to a portable version of Java can be quite useful in certain situations. You do however need to remember to update it regularly when a new version of Java gets released by Oracle, to avoid any kind of trouble with security issues or other issues that are fixed with updates. (The article is an update to the first review of Java Portable which we have published back in 2010)