Catching up with the Keynoters

Road to JAX London – A chat with JClarity’s Martijn Verburg and Kirk Pepperdine

Chris Mayer

With JAX London just around the corner, we caught up with the Keynoters. Our second chat is with Java performance masters Kirk Pepperdine and the Diabolic Developer, Martijn Verburg.

 and Big
Data Con
 are just a few weeks away and naturally, we’re
very excited about what’s in store for the events. It seemed like
the perfect time to catch up with those keynoting at the event
itself in what we’re calling the “Road to
 series, which will cover some important topics
for the worlds of Java and Big Data.

Next up is the delightful duo of the Diabolical Developer
and LJC co-leader, Martijn
and Java Champion and performance tuning guru Kirk
. The two will be speaking just before JAX London
Community Night with their keynote ‘Java and the machine’.
We caught up for 30 minutes to talk all things Java (cloud,
modularity and mobile mostly), JClarity (the Java performance
company they’ve just launched with Ben Evans) and some important
community stuff. Enjoy!


JAX: Obviously, you’re both keynoting at JAX London with
‘Java and the Machine’. Without giving too much away what is it

MV: Basically, the physical environment that Java developers,
and that Java itself is running on, has actually now changed in the
last couple of years and is continuing to change. We see two major
changes. One is the fact that CPUs have gone multi-core, which
means the program runs very differently under that piece of
Also, the fact that a lot of people are
moving toward virtualised operating systems, which means a lot of
people are no longer running on what we call ‘bare metal’. This is
a new paradigm that Java developers have to get used to and take
advantage of, as well as Java the language and platform itself.
We’re going through this quite interesting period of change.

KP: You’ve put a positive spin on it, I’ll put a negative
one on it. Hardware is changing and a lot of that change is for the
better. It is making lives more difficult for developers because
they have to think about things they didn’t have to think about
before. However the platform running on, in terms of the
virtualisation, is actually – well you know, the better they make
the hardware, the more things we can think of to consume it. A lot
of performance challenges when you move to a virtualised
environment. In other words, it’s not a straight bare metal to
virtualised environment switch and everything’s going to work the
same. It doesn’t work that way. I like to tell people that there’s
plenty of good reasons to move to virtualised environments –
performance isn’t one of them.

MV: Absolutely not.

KP: There’s many cases of moving to virtualised environments
is going to cut people off from some of the advances made in
hardware, and make it more difficult to get at things and make
their deployments prone to different types of failure. So it’s not
completely a panacea – although there are some obviously advantages
to virtualised environments. There’s a lot of people to be solved

JAX: Do you think developers don’t embrace multicore now,
will they get left behind?

MV:They will be left behind, absolutely. Dead in the water.
It’s adapt and survive and don’t adapt and die. It’s Darwinism at
its best.

JAX: Simple as that?

KP: It’s worse than that – they’ve already been left behind.
We’ve been telling them from 2005 to start adapting. In seven
years, if they haven’t started adapting, you wonder what they’re
going to do with the new changes in hardware and the new resources
available. How are they going to even consider taking advantage of
those resources?

I’m not saying it’s an easy slog to adapt to multicore
environments. There’s a lot of interesting intricate problems that
require a lot of thought in order to work your way through them.
Our simple pessimistic lock-on type models we’ve been using in the
past – they simply won’t scale. We actually have to be more

Fortunately in Java, we have an advantage in that we have
these very clever library writers helping us. A lot of developers
can accidentally move to multicore.

JAX: Do you think a change of mindset is needed – is it as
simple as that or is there more to it?

MV: It’s not just a change of mindset but a willingness to
knuckle down and practice. There’s the old adage that you won’t
become a world expert unless you do something for 10,000 hours and
we’re not saying they have to go to those extremes.

KP: Sure they do!

MV: (laughs) Kirk would argue otherwise. If a number of
developers have the discipline to sit down and learn even the
existing libraries, which have been there since the mid 2000s,
[then] it’s very much a case of knuckle down and learn the stuff or
be left behind.

JAX: Do you feel like Oracle are doing enough to embrace
this issue?

KP: Absolutely.

MV: I have to agree. They’re putting in an awful lot of
effort. If you look at the work being done on Java 8. Lambdas isn’t
simply about reducing a nice bit of boilerplate source code for
developers and not even necessarily all that much about adding the
functional programming aspect to Java. What it’s real power is is
enabling parallelism inside a lot of the default collections,
libraries, other APIs inside Java itself. All of sudden for
completely free, developers are going to have collections which
work really nicely on multicore machines. That takes a massive
amount of engineering effort on behalf of Oracle.

KP: It even goes historically before that. When people were
predicting that we’re going to have trouble with what to do all
these transistors, Oracle looked at this and said “Crap, our
database speed is coupled to clock rates.” If there’s no more free
ride in getting high transactions based on clock speed improving,
what are we going to do, right?

They started a long time ago, even pre-2000, looking at
what investments needed to be made in order to continue their
dominance in the database space. I think that they’ve been thinking
about this for a long time. Sun had been thinking about this for a
long time. If you look at the post-Sun era moving into Oracle,
they’re continuing to think about it. It’s been going on for a long
time and will continue to go on. If you get a brand new piece of
hardware, you come with 800, albeit limited cores on your machines
that aren’t utilised. Oracle’s already started a project saying
“How can Java take advantages of those 800 cores sitting there
basically drawing triangles.”

JAX: Do you think this is the biggest challenge Java faces
– is this the one?

MV: In terms of Java on the server, I think it is one of the
biggest ones. In terms of keeping Java the language and platform at
the forefront, I guess, [at the height of] consumer awareness, Java
needs to have a stronger story in mobile.

At the moment, you’ve got Android, kind of Java-based but
we all know the conflicts over that. That’s probably the only piece
puzzle missing. Modularity would have helped there, so Jigsaw. It’s
a real shame it got delayed, I do think it was the right call to
delay because it simply wasn’t baked in well enough. It’s certainly
one of the biggest challenges Java faces but I actually think this
side of it is going reasonably compared to the others.

KP: I think we’re far ahead on that front and there’s no
doubt that something very disruptive could come along change the
picture very quickly. I haven’t seen what that is yet and
certainly, that’s not where the problems are. The biggest problems
are the apparent lack of presence on mobile devices.

JAX: Is that the key hindrance for you then?

KP: I wouldn’t say it’s a hindrance. When I look at the
future of computing, I don’t see laptops or desktops there, per
say, but I see server rooms and people running around with mobile
devices, or even something more mobile than a mobile device. In
those cases, you have to say that when it comes to the big iron as
Marty has pointed out, Java is a clear obvious choice

But when you move into the mobile space, I would even be
as bold to say, I’m not sure the VM technology as it is implemented
today, as it works against the hardware today, is actually a good
solution for mobile devices. I think that’s going to be a struggle
– how do we change the technology so that it does fit in that
particular space? I think Jigsaw would have helped, but it’s a very
small piece of the puzzle. You have to look at how the VM works and
that’s what I think Google did when they looked at Dalvik and they
said how can we make this better for a mobile platform. They come
up with their solution – is it the best one? I don’t know, it’s
certainly better than the alternatives at the moment.


JAX: Let’s move on to JClarity. How did that come about and
the goals behind setting that up?

MV: It’s a kind of a convoluted story. There’s three of us –
Kirk, myself and Ben Evans. We’ve known each other quite some time
on the conference circuit, mailing lists, talking about the JVM and
performance and also fun tech stuff. A couple of years ago, Ben and
I were working on a book together and we decided that was going
quite well and we wanted to start a company together.

We kind of bandied around some ideas but nothing was
sticking, all that much that we felt would be an industry changing
or industry significant idea. At that time, Kirk had kindly invited
us to teach his performance tuning course. After teaching that a
couple of times, a lightbulb went off in our heads, and we thought
Kirk has actually done this for so long and got this brilliant
methodology which despite being slightly experimental, kind of

KP: Kind of works?

MV: You can turn it into software. We approached Kirk
straight away and said “Hey, want to turn this into software?” and
he turned around and said “I’ve been waiting to do this for 10
years, why didn’t you guys ask me earlier.” That about sum it up

KP: That about sums it up

JAX: What is the raison d’être of JClarity and the company
moving forward?

KP:  Really in my mind, it’s about disrupting the
performance space. It’s not a black art, or magic. It’s not
unpredictable, there’s a lot of predictability here. There’s a lot
of things we can do to actually further, for the lack of a better
word, the science of performance tuning so that we can actually
tool a lot of this stuff, so we can basically “professionalise” the

MV: Turn it into a empirical science – we believe that it is
and we’ve proven that it is. Kirk’s passed 15 years of teaching and
putting this stuff into practice, and Ben and myself and have been
doing for quite some time. There’s actually a small sort of loose
community of us who have always had this feeling and it never
really banded together. Now it’s starting to happen.

JAX: Do you think a lot of the work is to dispel myths for
Java developers – are some developers wary of trudging into those
waters without making too many mistakes?

MV: Absolutely. I was just teaching this week in London and I
had six very bright Devops/developers. All tech leads and senior
developers. Lightbulbs were going off all the time. They’d go “But
I read this blogpost that said to do this or my admin manual told
me to do that, or my old mentor told me to do this.” They never
actually sat down and just measured things like any normal
scientific process. Once they started doing that, with the
experience and intelligence they naturally had, they were up and
flying in a couple of days. And they were all really excited to go
back and apply it in their day jobs.

KP: We don’t really teach anybody anything new – it’s about
refocusing how they think about problems. That’s the most useful
thing they come out of the course with. Once you get the right
measurement, it’ll give visibility into what’s going on and if you
don’t have that, you don’t have the right measurement. You just
need to learn how to get it.

JAX: I’m guessing some developers don’t have that vision
already available to them?

KP: I’ve had conversations with a number of departments at
universities that were asking “How do we teach this because no one
teaches it?” Performance tuning is something that isn’t taught.
It’s expected because we’re in this industry where everything
blazing fast. We’re supposed to know it just naturally and what I
find is that it’s not a skill developers come out of school
naturally, so when they actually have to go do it on the job,
they’ll do it.

Some people will be naturally good at it and other people
will come along and be less good at a particular aspect. They’ll
run into roadblocks. People come up with their own way of doing
things. What we’re trying to do is get past these naive approaches,
and say here’s some best practices, filtering them over time to
figure out which ones don’t work. We toss out things that don’t
work and even our process has to adapt to our changes in hardware
and technology stack. Because when things do change, we’re going to
find there’s modifications that we might have to make to the
process in order to keep up.

JAX: There seems to be a lot surrounding the cloud on
your website, right?

MV: The reason we’re aiming for a cloud – actually it’s a
multitude of reasons. One of the big reasons we’ve seen the trend
for a while now that Java and the JVM is going to dominate on the
cloud going forward. It’s really the only platform that can handle
the scalability requirements. However, there’s still this element
of Java performance tuning being a black box and what we really
hope to do is give illumination, clarity and light to people who
have to administer hundreds, thousands of VMs. That’ll hopefully
make the entire cloud story a bit more stable and better for
everyone really. We want to become the heart and soul of these
cloud platforms.

KP: If I could be so brazen to say on the scalability
issue – there isn’t a product out there that will scale into the
cloud as we expect cloud deployments to scale.

That’s the first problem: the second is that all the tools
require an extrordinary amount of knowledge of all the different
bits of the systems. If you combine those two things, it really
means, you’ve got a lot of problems with the current toolset. We
think that it can be done better. We certainly want to be scalable
so we understand the problems that cause things not to be scalable.
So we’re trying to avoid them up front. People to have to be rocket
scientists to have to work tooling.

JAX: With low-impact?

MV: Absolutely. We sit on the other side of the fence when
we’ve been working at enterprises in our careers. We’ve had vendors
come in with these performance tools and they’ll make claims like
“this will have a tiny footprint on your application” and every
single time, the performance tool becomes the performance
bottleneck. It’s really frustrating and we’ve flipped it on its
head, and said this is our first requirement. Not getting at the
data, not looking at pretty graphs – our first requirement is to
make that whatever we build genuinely has very little to no impact
when it runs.

KP: I like to say that we’re a guest on our customer’s
hardware and we want to behave that way. Low footprint, low impact.
A lot of tools claim to have it. When you actually look at what
they’re doing, you find that they can get moderate amounts of
scalability in a lot of cases, and some can scale relatively pretty
good. But when you get into larger deployments, they start falling


JAX: Do you think enough’s being done in core Java
development to work towards the cloud? A big question, I

MV: It’s a big area – they’re certainly thinking about, but I
guess even the really smart engineers at Oracle and OpenJDK are
going into the deep unknown a little bit. We’re not convinced all
of the right work has been done or right decision are being made.
But then again, who does really know? No one’s done this

Google talks about their Go programming language, which in
theory, is being designed for a lot of these problems, but even
that hasn’t been proven yet either. There needs to be some
exploration, and we’re hoping the OpenJDK and Oracle are going to
be reasonably flexible and try out ideas and use the community as
much as possible, to actually test ideas out really early and fail
fast. Then go down a direction which will help Java and JVM scale
in the cloud than it already does.

JAX: With the London Java Community being on the JCP, are
you happy with the progress being made with,

MV: Very happy with the progress. We set out an internal goal
as part of the LJC User Group, of changes we wanted to see, in the
standards in general around Java. For us, we’re about a good 5-6
months ahead of the curve where we expected to be, so we’re really
pleased. A lot has been driven by Oracle and the other big vendors,
and that keeps surprising people. They want to open things up
because I think they realise the value that the bigger they make
the pie, the more everyone gets a bigger slice. It’s in their best

JAX: Would you like to see more JUGs on the JCP? There’s
two at the moment in SouJava and LJC – are more

MV: I actually think the balance is quite good with two of
us. We did all vote together to reduce the size of standards body.
Too many cooks spoils the broth, a decision never gets made. The
Executive Committee is being reduced to between 20-25 people. If
two are User Groups, or at least representatives from the
community, then I think that’s a decent

JAX: Adopt a JSR, it’s been a year since that initiative
started. How’s that going and how is it moving

MV: It’s going really well. We’ve actually got a whole swathe of
events at JavaOne, in and around Adopt
. The community keynote will touch upon it for 10 minutes,
and there’s workshops etc. At the moment, it’s probably at the
stage where we’ve got a few large Java User Groups around the
world, which have all banded together and are working on these
things. The next stage is we want this to be applied. At the
moment, the Chennai JUG in India, SouJava in Brazil, ourselves in
London. We really want to see the French become part of it and
others. We’ve had conversations with all the Java User Group
leaders and the intentions are all very positive. What we’re now
focusing on is giving more practical guidance on how they can go
about running workshops and give feedback. That’s the only thing
really stopping this thing from taking off: how on earth do I run
this and get the right feedback?

JAX – Great to hear. Thanks gentlemen for chatting to us,
and we’ll see you at JAX London

For more information about JAX London – the conference,
speakers, keynotes and venue – visit the website. JAX London takes
places October 15th-17th.

Picture courtesy of MP4

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