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vJUG write up: Wave Gliders and Java, with James Gosling


The first session in 2015 for the vJUG was a huge hit and historic for the vJUG, as wow, we hosted the Java creator, James Gosling. In case you missed it or want to watch it again, the replay is just below. James talks about his project at Liquid Robotics, for whom he is CTO, called the Wave Glider.

This post includes an exclusive interview James Gosling gave to the head of RebelLabs, Oleg, our recap of the session and the full video of the session itself.

Oh and if you wanted to join the vJUG, it’s free to join and you can do it really easily here. Do it!

So what is the Wave Glider? Well, it s 2 part craft which has a surf board style float that stays on the surface of the water with a sub style robot that remains submerged beneath which harvests energy from the waves and produces approximately 1000 lbs or 450kg of thrust. The two pieces are connected with a cable. The float has satellite antennas for communication and solar panels for power generation. Here you can see it in action:

Communication with the Wave Glider is typically via the Iridium satellite network and this is super expensive with costs of $1/KB – yeah, thats $1000 to transmit a small 1MB image! Well, you can’t just get 3G out in the ocean, right!

So what’s it used for? Well, the Wave Glider has already been used for pollution monitoring, global warming studies and seafloor studies for tsunami detection among other things.

One really interesting part of the session was hearing James talk about some really unusual concerns, in the development of the Wave Glider. For instance, high seas can cause a big problem with the mobility, plus of course the unit is surrounded by salt water. Imagine your data centre was covered in a highly corrosive substance :) Oh and shark attacks! No kidding, one of the wave gliders was involved in a shark attack which clipped one of the wires, and from the image below, you can see the shark teeth marks to the right hand side taking off the white paint.

Screenshot 2015-01-23 11.58.04

To quote James when asked about how similar some of the challenges were to something like space travel he said “I’d take radiation over sharks any day”.

Let’s get deeper into the implementation

In terms of tech, Java SE embedded version 1.7 runs on the ARM hardware, and James mentioned they’d like to upgrade to version 8 soon. Regulus is the main control software which runs on the box, on top of TimeSys Linux, because it was one of the few that had the drivers for the ARM boards they’re using. So far there hasn’t been a single JVM failure on any of the devices. There’s also a jetty server which hosts a management console to view the components, if you’re near to the board. The software services that are created are pretty much all built on top of servlets and JavaBeans.

The component model used is services based with an interesting lifecycle management which kinda looks similar to OSGi. To use a service you can easily annotate a variable and allow injection to provide you with that service. Services include communications, location, orientation, situation, power, navigation and many more. Testing is done via a simulator, so the entire environment is run is a simulation mode where simulations can be run through and later you can device which options to use.

Oh and you think debugging is hard with Eclipse? Check out this photo of James doing some real debugging!

James Gosling debugging a rudder

For more on this session, be sure to check out the full video at the top of this post.

Exclusive Interview

Oh and in 2015, we’re going to be interviewing all vJUG speakers, so Oleg started by interviewing James Gosling. Cool, right?

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