Closures for Java 7

Yes it's true! Java 7 will indeed have closures. I was enthusiastically following the Java closures war in 2007, and subsequently had lost hope that Java will ever have closures. But now it seems like the heads at SUN have changed their minds after all. This was announced by Mark Reinhold at devoxx.

Let's hope they do it right. Which of the various closure proposals will be used? Apparently it will be a mix of them all. Syntax-wise it resembles the simplistic FCM proposal, semantic-wise it partly uses the BGGA approach: seems like assignments to captured non-final variables could be in, but non-local transfers will be out (using break or continue within closure code will yield a compile-time error). Sadly this also strikes out BGGA's innovative control-statement-invocation syntax. Anyway, they have changed their decision once so there is still hope for more BGGA support.

Some quick links pointing to various sources of this news:

• Alex Miller's blog
• a summary of Mark's talk at devoxx
• closures mailing list at java.net
  
• Neal Gafter's current closures proposal 0.6a (simplified BGGA)
  

Updates:

Catched a comment from Neal Gafter on Ted Newards blog:

I had been discussing this spec [BGGA 0.6a] with Gosling, but I have had no contact with Reinhold.

And another one on Cay Horstmans blog:

the 0.6a specification is NOT BGGA, nor is it intended to document Mark Reinhold's plans for JDK7. [...] it resulted from a discussion with the other authors of the BGGA spec culminating in this document a couple of weeks ago [...] I was attending PDC09 when I read a tweet about closures and put up the link. I think the timing and similarity to Mark Reinhold's announcement are either coincidental or Gosling has passed it on to him. [...] Note that this spec allows access to non-final local variables from the enclosing scope, which rumors suggest Reinhold has ruled out.

It's a shame Neal does not blog about closures himself anymore.

Top 100 Blogs for Development Managers (Q3 2008)

There is a new list containing the top 100 blogs for development managers. No, my blog is not listed there ;-), though I am a happy reader of many of the top blogs. I don't know why the list is titled "for development managers", most of the blogs listed there should be interesting for any developer, like me.

How to export eclipse workbench layout (or perspective settings)

Do you find yourself in the need of configuring your eclipse workbench layout on every new computer you are working on? I did. I am used to a personal workbench layout. Unfortunately eclipse (version 3.3) does not seem to provide means for exporting workbench layout or perspective settings and importing them on another machine (if you know a way I am not aware of, please let me know). Eclipse provides build-in means for exporting some user settings such as keys, formatter and cleanup but how do you export your workbench layout or perspective settings?

My answer to this question is a little bit hacky, but it works. Go to your eclipse workspace directory in your file system and find the folder workspace/.metadata/.plugins/. This folder contains all the configuration you have made in your workbench. You don't have to copy all contents of this folder to achieve the goal of exporting your perspective settings or workbench layout. In particular the following folders are interesting:

workspace/.metadata/.plugins/org.eclipse.ui.workbench/

This folder contains all your perspective settings and your workbench layout. Copy this folder and its contents and save them in the workspace of the other computer.

workspace/.metadata/.plugins/org.eclipse.core.runtime/.settings/

This folder contains all the settings you have made in the eclipse preferences. Eclipse provides build-in means for exporting some of them, but copying this folder works also.

There may also be other folders in the .plugins directory you are interested in. They all contain preferences and settings for some build-in or installed eclipse plugins.

Google's Android is here

If you are into mobile device development and havn't heard about Android yet, you should go check it out now. In short, Android is Google's (and partners) new platform for mobile devices. It consists of a linux operating system and an SDK that sits on top of the Java programming language and a custom Java VM named DALVIK, which is specifically designed for embedded and mobile devices. I am currently soaking up the Android documentation and API and I am eager to build my first Android application.

This is a very exciting moment for all Java and Google enthusiasts and a milestone in the history of mobile devices. Unfortunately the first Android devices will not come before late 2008, and even later in Europe, but this is not reducing my excitement.