java – mikewilliamson.dev

A while ago I gave a talk at the Ottawa graph meetup about getting started doing graph data visualizations with Gephi. Ever the optimist, I invited people to install Gephi on their machines and then follow along as I walked through doing various things with the program.

java_install

What trying to get a room of 20 people to install a Java program has taught me is that the installer’s “Java is found everywhere” is not advertising; it’s a warning. I did indeed experience the power of Java, and after about ten minutes of old/broken/multiple Java versions, broken classpaths and Java 7/8 compatiblity drama, I gave up and completed the rest of the talk as a demo.

All of this was long forgotten until my wife and I started a little open data project recently and needed to use Gephi to visualize the data. The Gephi install she had attempted the day of the talk was still lingering on her Ubuntu system and so it was time to actually figure out how to get it going.

The instructions for installing Gephi are pretty straight forward:

Update your distribution with the last official JRE 7 or 8 packages.
After the download completes, unzip and untar the file in a directory.
Run it by executing ./bin/gephi script file.

The difficulty was that after doing that, Gephi would show its splash screen and then hang as the loading bar said “Starting modules…“.

If you have every downloaded plugins for Gephi, you will have noticed that they have an .nbm extension, which indicates they, and (if you will pardon the pun) by extension, Gephi itself is built on top of the Netbeans IDE.
So the next question was, does Netbeans itself work?

sudo apt-get install netbeans
netbeans

Wouldn’t you know it, that Netbeans also freezes while loading modules.

Installing Oracle’s version of Java was suggested and the place to get that is the Webupd8 Team’s ppa:

sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java8-installer oracle-java8-set-default
# The java version that got installed:
java -version
java version &amp;quot;1.8.0_72&amp;quot;
Java(TM) SE Runtime Environment (build 1.8.0_72-b15)
Java HotSpot(TM) 64-Bit Server VM (build 25.72-b15, mixed mode)

That finally left us with a working version of gephi.

Installing Gephi on Arch Linux was (thankfully) drama-free, but interestingly installs the OpenJDK, they very thing that seemed to causing the problems on Ubuntu:

yaourt -S gephi
java -version
openjdk version &amp;quot;1.8.0_74&amp;quot;
OpenJDK Runtime Environment (build 1.8.0_74-b02)
OpenJDK 64-Bit Server VM (build 25.74-b02, mixed mode)

It’s a mystery to me why Gephi on Ubuntu seems to require Oracle’s Java but on Arch I can run it on OpenJDK.
With a little luck it can remain a mystery.

I have been playing with some JavaFX stuff for a little while now and finally gotten to the point where I am trying to deploy my first program. I was a little naive inn thinking this was going to be an easy process and have been forced to have a good hard look at jnlp files. It turns out that most of your apps deployment options are controlled by editing the XML in that file. After a little reading about the different fields I set to tweaking them to see if I could get the effect I was looking for. After making my changes I crossed my fingers and relaunched my app.

No change.

Check my syntax,

No change.

Try some variations.

No change.

Try to effect any change whatsoever by editing fields I know are working like <vendor>Mike Williamson</vendor>.

No change.

A little poking around reveals that Java is thoughtfully caching the jnlp file and has been totally ignoring all my changes since the first time I loaded the app. Thanks Java. I’ll appreciate that someday.

Under windows go to Control Panel > Programs and open the java control panel. Under Temporary Files settings click “delete files” as shown below and suddenly everything works. Yay!

Tag: java

Running Gephi on Ubuntu 15.10

Editing JNLP files – gotcha!