But that’s impossible, or finding out that the JIT has broken your code.

Every now and then you look at some code and think that it cannot be possibly be wrong. Once you have ruled out a simple programmer screw up / enemy action in code (Make sure you read Java Puzzlers or similar) or a concurrency issue (Read Java Concurrency or go on Dr Heniz excellent course) you should sit back and take a few days and then starting thinking about whether the JDK is indeed (more...)

Exciting things happening in Coherence…

I hope everyone is attending/watching JavaOne 2014 tomorrow.   There’s a sneak preview of some cool next generation Coherence with Java 8 in the Java One Technical Keynote

Follow @JavaOneConf and @pinocchiocode to find out more…

Oracle SOA Suite 12c tips – Tuning the SOA infrastructure thread pool

One of the new capabilities of Oracle SOA Suite 12c is the ability to control the SOA infrastructure thread pools, except the resource pools for EDN and the adapters, with Oracle WebLogic Server work managers. Each partition will has its own work managers defined. This allows you to separate services in partitions and, to some extent, tune them separately based on for example specific SLA requirements.

Well, this blog posting is not about explaining the (more...)

Open Source as religion – when the Bazaar becomes a Cathedral

The seminal book on Open Source development "Cathedral and the Bazaar" talks eloquently about the difference between commercial software development and open source development.  In the past few years however there has been another shift, a shift where companies are actively releasing their technology into Open Source as a competitive differentiation.  A claim of 'we are open' because the source

Share your source between projects

Normally we pack functionality into libraries and use this library to share the functionality. However, during development of several JDeveloper Extensions our goal was to have one shared java source between our JDeveloper 11g and JDeveloper 12c extension.
Off course we wanted the ability to easily develop, test, debug and run the extension, but we also want to share the java code to introduce reusability.

We accomplished this, by creating a separated ‘coresrc’ folder and (more...)

The next big wave of IT is Software Development

I can smell a change coming, the last few years have seen cloud and SaaS on the rise and seen a fragmentation in application development (thanks in a large part to the appalling stewardship of Java) and a real focus of budgets around BI and 'vanilla' package approaches.  Now this is a good thing, both because I jumped out of the Java boat onto the BI boat a few years ago but also because its

Software Development Wave 4: back to the package

The end of the next Software Development wave will be when Software development against 'eats itself' as it did with with technologies like Hadoop showing a new value in information, with platforms like SFDC showing new pre-build services, where people like GoodData have turned BI into SaaS.  So we will see the same evolution again and a new generation of commoditisation which drives

Post-hoc tracing using a debugger

Once nice little features of most debuggers that I have been exercising recently is the ability to log information on a breakpoint. This can be a really useful was to understand code without having to modify it is involve byte code modification.

Let's consider this very trivial and inefficient implementation of a function to return the n'th number in the Fibonacci sequence.

public class Fib {

    public long fib(long number) {
        return number < 1 ? 0 :    // Breakpoint here
            number < 2 ? 1 : fib(number - 2) + fib(number - 1);

    public static void main(String[] args) {

        Fib fib = new Fib();



Now we (more...)

Lambda’ery WebSocket code (from UKTECH13 presentation)

At UKTECH13 I was asked to post the source code to the WebSocket used in my presentation, primarily because it was using JDK 8 constructs that were unfamiliar to many. One of the very nice things about the changes to the languages and the supporting library changes is the lack (more...)

TechTalk: Java Garbage Collection – Theory and Practice

Below are slide decks for open event held in Moscow Technology Center of Deutsche Bank.

Topic of event was garbage collection in JVM.

Part 1 by Alexey Ragozin

Part 2 by Alexander Ashitkin

TechTalk: Virtualizing Java in Java

On 12th December, I was speaking at JUG in Saint-Petersburg, Russia.

It was a long talk about using NanoCloud.

Below is video

and slide deck from event

My history with Big Data

Before I joined Cloudera, I hadn't had much formal experience with Big Data. But I had crossed paths with one of its major use cases before, so I found it easy to pick up the mindset. My previous big project involved a relational database hooked up to a web server. (more...)

HotSpot JVM garbage collection options cheat sheet (v3)

Two years ago I have published cheat sheet for garbage collection options in HotSpot JVM.

Recently I decided give that work some refreshing and today I'm publishing first HostSpot JVM options ref card covering generic GC options and CMS tuning. (G1 have got a plenty of tuning options during last (more...)

JVM deep dive at HighLoad++ 2013 (Moscow)

Today was speaking at HighLoad++ 2013 Moscow. I had two presentation covering deep internals of JVM. One about JIT compilation and other concerning pauseless garbage collection algorithms.

Slide decks are below (in Russian)

Java class finding tool: ClassFinder

I got into more coding again lately and that is a good thing I think. I’m a believer of the German saying “Wer rastet, der rostet” or in English: A rolling stone gathers no moss! Java seems to be my main programming language since quite a while now. But believe (more...)

Oracle Forms and Java 7u51

Java 7u51 is scheduled for release in January. It will have some consequences for you Forms installation that you need to address.

As far as I know there is no problems with using 7u51 on the server side, only on the client side.


Jar signing

7u51 requires you to sign all RIAs (Applets and Web Start applications).

Oracle already signs the standard jar (more...)

WebLogic Server and entropy

After input from Jacco H. Landlust and Edwin Biemond I have rewritten my post about entropy.


Entropy pool

In computing you often need random numbers. They are used for encrypting stuff but also for lots of other things.

For Linux servers random numbers are default provided by the /dev/random device. /dev/random is a pool of random bits (more...)

Write an auto-debugger to catch Exceptions during test execution

Previously I have stated that there are some exceptions you would always want to keep an debugger breakpoint on for. This help prevents code rotting away without you noticing - sometimes masking a different problem.

If you take this seriously then it is a good idea to extend this idea (more...)

SJK (JVM diagnostic/troubleshoting tools) is learning new tricks.

SJK is small command line tool implementing number of helpful commands for JMV troubleshooting. Internally SJK is using same diagnostic APIs as standard JDK tools (e.g. jps, jstack, jmap, jconsole).

Recently I've made few noteworthy additions to SJK package and would like to announce them here.

Memory allocation rates (more...)

Almost named method arguments in JDK 8

Sometimes it would be really nice to have named method parameter in Java, this doesn't look likely for a long while but there is always another little work around, for example using a builder pattern to get similar behaviour, that will bridge the gap for a little bit. It occurred (more...)