This was my first JavaOne.  At first I was amazed at the spectacle of it all.  Logistically there's a lot going on.  When I signed in I was sent to about 6 different locations before I had all of my credentials and gear.  Despite the bumps it's the place to be if you're in the Java world.  OpenLogic had a booth at the event and it was very wise for us to be there.  The booth was always hoppin' with attendees that wanted to know more about what we do.

The sessions were good.  At JavaOne there's plenty of opportunities to hear notable people.  I saw James Gosling, Rod Johnson, Simon Phipps and Eben Moglen.  Most of the talks were great, I got exposed to interesting technologies that I'm eager to play with.  There was some overly buzzword compliant talks that didn't deliver on content.  I also wish it were a smaller show so you could grab speakers and bounce ideas off them in between sessions.  But if it were like that then it wouldn't be JavaOne.  It was fun from a general perspective to just be around a ton of people jazzed about technology, all in all a great experience.

This is an ultra-brief, brass-tacks, rubber meets road description of what Sun's decision to open source Java means for the average developer. Someone asked a question about what open sourcing Java meant and I was surprised I didn't have a good answer. So not much opinion or independent thought here, this is just a summary of what I've found out. I'm not a lawyer, yada yada. Don't consider this legal advice.

What's it mean?

The good news is that (going forward) Java will always be an open platform for development. No one is going to hijack it, it won't become abandonware. But with such an important platform there's always the danger of forking. Fortunately the key players have promised to keep the JREs compatible.

Read below about the Classpath exception, the new GPL Java is not viral. Usage of the Java platform is business as usual!

What license?

Sun chose GPL v2 for Java SE, Java ME, Java EE implementations. No open source zealots can see this choice as a weeny move, Sun is all in. You can get all code for JDK6 and JDK7 under the Java Research License in the meantime. As indicated in their FAQ, this isn't a vote against GPL v3, Sun just went with the version that's already out.

Here's one mans summary of the GPL.

You can re-distribute this stuff and even charge for it. But if you make modifications to the software you need to provide source code so that others can benefit from your modifications.

What will be open sourced?

Java SE, these are early versions of the JDK7 release. All will be GPL v2 + Classpath exception

• Java compiler javac
• Java HotSpot virtual machine
• Java class libraries
• JavaHelp 2.0 (JSR 97)

The GlassFish Java EE application server will be GPL v2 with Classpath exception (actually it's dual licensed under the CDDL as well).

Sun is gradually releasing parts of their Java platform. They're not releasing everything because of licensing issues. They refer to it as not releasing encumbered code that Sun doesn't have rights to open source legally. Look for this code to be early targets for open source clean room implementations.

The Classpath exception

The Classpath exception that Sun adopts for open source Java is an innovation of the GNU Classpath project. The GNU Classpath project is a GPL v2 implementation of the JDK by the GNU folks.

The Classpath exception means that code that you write to the GPL v2 Java APIs aren't required to adopt the GPL v2. This removes the possibility of the often misunderstood viral nature of open source technology. Businesses can continue to develop on the Java platform taking advantage of an open source community while still making money from their efforts and applying whatever license they prefer. However if you take the source code for the Java APIs, modify and distribute those, then the derived work needs to be GPL v2. Other than that, you have no fear of infection.

Basically the Classpath exception makes the license on the APIs very similar to the LGPL. The Classpath serves as a firewall between the GPL v2 and users of the Java APIs. There is precedent in the open source Java world to use the Classpath exception (by the GNU/ Classpath project) so Sun went with that.

The forking danger

Will IBM try to eclipse Sun with their own blue JDK? Will Microsoft embrace and extend, remember J++? The open source implementations (GNU/ Classpath and Harmony) have promised to build fully compatible implementations of Java SE.

Sun will still be the gate keeper for the Java Compatible and Java Powered brand and logo. Others can fork such that they have an incompatible JRE but they won't receive the special Sun seal of approval.

Licenses

• GPL v2
• Classpath exception The Classpath exception means that you can code your Java applications to these GPL v2 APIs and not have to conform to the GPL v2 license.
• Java Research License
• CDDL

This FAQ was very helpful for the details of what opensource Java means. http://www.sun.com/software/opensource/java/faq.jsp

I used to have street cred.  I was a hardcore VIM user.  When I was still in college and new to Unix I would find some cheezy editor like pico and stick with that for coding.  Finally I ended up on an HP-UX box with nothing but vi.  When the sys-admin told me it'd take a few weeks for him to get around to installing an editor with training wheels (his version of 'go away kid') I decided to dive into vi.

I found VIM and used it on Windows and Linux for all of my development.  It painful at first but after the steep learning curve I was slinging code incredibly fast.  I used vim for about the next 6 years doing real world development.  I had a tweaked out .vimrc and wrote custom Python scripts to do code generation from database schemas and automate boring tasks.  I had it set up to do code completion using ctags.  I even wrote an article on using VIM and Java that I still get pings about.

Then I ended up in a shop that required Eclipse.  So reluctantly I went over to the dark side.  It was painful navigating.  Fast forward to OpenLogic where sensibly you can use any IDE whatever you want, as long as the job gets done.  I thought I'd give my old VIM love a go.

No dice, I've grown used to the code completion, the version control integration and all the other niceties of a modern IDE.  Begrudgingly I decided to go back to Eclipse.  Enter the Eclipse VI plug-in.  I'm giving it a try and I'm very impressed.  It's just the best of both worlds; easy navigation and editing with all the comfort of an IDE.

I guess it's progress.  I remember the sun coming up after a night of trying to get my mouse to work, hacking at an XF86Config file on my Slackware Linux 486 laptop.  Now there is virtue in things just working.  I'm a big Ubuntu fan for that reason.  Nothing to prove anymore, it's not about technology it's about getting things done.