Skip to main content

Jazoon 2007: Some more notes on last day

I'm just back from some dubbin' in Publin, I mean pubbin' in Dublin, so little time to write a full post. However, I did find the notes I lost from day 4 in Jazoon:


Last Day. Neil Gafter on closures.

First talk OSGi from Ergon Informatik.

The speaker is really happy with OSGi. It's great, it works really well, etc. Running osgi demo.

Bundles/plugins managed in a phone on a console app called J9 Console.

Goes on to talk about RCP. eSWT for embedded. Subset for SWT. Can run without RCP/osgi context if you don't need them.

JFace, gui toolkit. eJFace for embedded.

eWorkbench lets you bundle simul apps running. eUpdate is the update mechanism that is in eclipse. Pretty cool, the whole update manager is run on an embedded device.

Services can be shared between apps in the same VM.

Issues they have encountered in eRCP. Useful list.

Use JFace fonts and typesets to avoid memory leaks.

Some negative experiences.. Complex bundle dependencies. The services have states to manage, and this can be tricky to learn. Plus all the usual embedded ui issues.


Web 3.0/semantic web Q&A session with Henry Story following the previous session that we unfortunately did not attend.. Very interesting.


Java and SecondLife.

Seems like SL has potential in using resources as in uri resources...

Abit about the SL script language. The scripts are only evalutated when in the SL engine, client side.

Scripts can also call http requests that the SL server will shoot off to external servers. 1 KB limit on the response. An example is a SL phone booth that shoots off SMS requests to external servers.

The 1KB limit can be workaround by having the SL object being able to respond with packets. Note that client code cannot be changed once deployed many places.

Communication is used between the client and an external server but needs to be done through a remote channel. The external server then XML-RCPs to the external server.

The java library (a port of the C# library) for utilizing SL clients is somewhat dead, appearantly. But offers good control.


Sort of split in half when it comes to deciding on the next talk. It's either a very interesting presentation on Jackrabbit or a talk from Netcetera on the complexity of software.

After talking with David about Jackrabbit for a little while I decided to jump in on the talk bout Build-up of artificial complexity. A talk straight to my heart.

Code grows ugly. We all know the problem, so what is the solution? Discipline and modularity are old solutions. Reduce number of (external) components is another one. I like addressing every req with an external component. His advice is be sceptical and choose the frameworks/components you *like*.

People don't like being constrained away from their personal favourite tech stacks. Limitation is dangerous, so don't restrain too much.

Will read more of this stuff. Read Greene's essay, but can't find the article on the net. Will just have to wait for the slides to come online (nudge nudge, Jazoon).

Popular posts from this blog

Encrypting and Decrypting with Spring

I was recently working with protecting some sensitive data in a typical Java application with a database underneath. We convert the data on its way out of the application using Spring Security Crypto Utilities. It "was decided" that we'd be doing AES with a key-length of 256, and this just happens to be the kind of encryption Spring crypto does out of the box. Sweet!

The big aber is that whatever JRE is running the application has to be patched with Oracle's JCE in order to do 256 bits. It's a fascinating story, the short version being that U.S. companies are restricted from exporting various encryption algorithms to certain countries, and some countries are restricted from importing them.

Once I had patched my JRE with the JCE, I found it fascinating how straight forward it was to encrypt and decrypt using the Spring Encryptors. So just for fun at the weekend, I threw together a little desktop app that will encrypt and decrypt stuff for the given password and sa…

Managing dot-files with vcsh and myrepos

Say I want to get my dot-files out on a new computer. Here's what I do:

# install vcsh & myrepos via apt/brew/etc
vcsh clone mr
mr update

Done! All dot-files are ready to use and in place. No deploy command, no linking up symlinks to the files. No checking/out in my entire home directory as a Git repository. Yet, all my dot-files are neatly kept in fine-grained repositories, and any changes I make are immediately ready to be committed:

    -> ~/.atom/*

    -> ~/.mrconfig
    -> ~/.config/mr/*

    -> ~/.tmuxinator/*

    -> ~/.vimrc
    -> ~/.vim/*

    -> ~/bin/*

    -> ~/.gitconfig

    -> ~/.tmux.conf    

    -> ~/.zshrc

How can this be? The key here is to use vcsh to keep track of your dot-files, and its partner myrepos/mr for operating on many repositories at the same time.

I discovere…

Always use git-svn with --prefix

TLDR: I've recently been forced back into using git-svn, and while I was at it, I noticed that git-svn generally behaves a lot better when it is initialized using the --prefix option.

Frankly, I can't see any reason why you would ever want to use git-svn without --prefix. It even added some major simplifications to my old git-svn mirror setup.

Update: Some of the advantages of this solution will disappear in newer versions of Git.

For example, make a standard-layout svn clone:

$ git svn clone -s

You'll get this .git/config:

[svn-remote "svn"]
        url =
        fetch = project-foo/trunk:refs/remotes/trunk
        branches = project-foo/branches/*:refs/remotes/*
        tags = project-foo/tags/*:refs/remotes/tags/*

And the remote branches looks like this (git branch -a):

(Compared to regular remote branches, they look very odd because there is no remote name i…

The Best Log Viewer Ever

This is what it looks like when I want to have a look through the logfile, to see what a user did on one of our machines one day:

Read the whole story about how it works on the Viaboxx Systems blog (and upvote on DZone!).

Microsoft ups their Git efforts another notch

This week Microsoft announced first class Git support embedded in the coming version of Visual Studio.

Now, it's not completely shocking. We could have seen it coming since Microsoft started offering Git repos on CodePlex, and more recently offering a Git client for TFS. In any case, these are some big news. Scott Hanselman weighs on some features and some more background here.

For those who are a bit unaware of what the Git situation on Windows looks like these days, I've dotted down these notes:
Some explanation on these:

msysGit has long been The Way to use Git on Windows. It's basically a port of Git itself, so it's a command-line tool.GitExtensions (includes Visual Studio integration), TortoiseGit, Git Shell, posh-git and most other tools are powered by msysGit.libgit2 is a native library for doing Git stuff. It is developed completely separate from Git itself. The above tools could (and should) probably use libgit2 instead of hooking onto and around msysGit.Github…