If you're following the content management space closely, but aren't a Java wizard, the JSR (Java Specification Request) numbers can become a bit of a puzzle.

I've recently had several conversations that went something like this. A vendor told me, "we've added JSR-186 support," (confusing it with JSR-168, which is not uncommon). So I replied, "you mean the JCR?" (guessing they may have meant JSR-170.) To which they said "yes, the JSR."

So as a public service, here are the four JSRs we hear most about in content management, with a short (and very colloquial) description:

• JSR-168, the Java Portlet Specification. This is the standard for the relation between a portlet container (portal software) and the portlets it can display. In theory, JSR-168 compliant portlets can be displayed in any JSR-168 compliant portal.
• JSR-286, version 2.0 of the same specification (with several improvements, e.g. the standardization of how portlets communicate with each other).

• JSR-170, the Content Repository API for Java. This is the definition of an API to access content repositories. Also known as JCR (the Java Content Repository). To confuse matters more, the standard only describes the API, but "JCR" is commonly used to refer to actual software. Such as Apache Jackrabbit, the JSR-170 reference implementation.
• JSR-283, version 2.0 of the same specification (which adds several functions the original specification was lacking, such as improved versioning.)

Of course, a blog post is much too short to give detailed descriptions of JSRs -- especially of all the differences between the original and the 2.0 versions. But at least, now you know the different terms to look for. (Our Portals and Web CMS research go into more detail about vendor compliance.)

If that makes you long for more confusion, check out Typo3. This is an open source project in PHP, but the upcoming new version 5 will have a repository modelled after JSR-283 (a Java standard)...