Pinging and Posting from PeopleCode

I had a need to Ping a server to see if the server could get to it.  I also tried to post to it.  This code could be helpful for others, so I want to share it.  A post should normally go through the Integration Broker, but I first developed it at a time when I had a product that was supposed to go on servers with diverse versions of Integration Broker.

The Ping code (more...)

Quick and dirty test for thread leakage in java

I was looking at a bit of code was leaking class loaders when deployed to tomcat - so I wanted to quick rule out that a background Thread was holding onto the loader. Pain by eye, it is quite easy with a few unix commands to process the stack trace, filter for the lines that contain the thread name, filter for just the thread names and sort:
sudo -u tomcat jstack 1853 | grep "  (more...)

So you’ve dumped 150 GiB of JVM heap, now what?

150 GiB worth of JVM heap dump is laying on hard drive and I need analyze specific problem detected in that process.

This is a dump of proprietary hybrid of in-memory RDBMS and CEP system, I'm responsible for. All data are stored in Java heap, so heap size of some installation is huge (400 GiB heap is largest to the date).

Problem of analyzing huge heap dumps were on my radar for some time, so (more...)

Découverte : Java Cloud Service Workshop


Binary search – is it still most optimal?

If you have a sorted collection of elements, how would you find index of specific value?
"Binary search" is likely to be your answer.
Algorithms theory is teaching us what binary search is most optimal algorithm for this task with log(N) complexity.
Well, hash table can do better, if you need to find key by exact match. In many cases, though, you have reasons to have your collection sorted, not hashed.

On my job, I'm (more...)

Moving My Beers From Couchbase to MongoDB

See it on my new blog : here Few days ago I have posted a joke on Twitter Moving my Java from Couchbase to MongoDB pic.twitter.com/Wnn3pXfMGi — Tugdual Grall (@tgrall) January 26, 2015 So I decided to move it from a simple picture to a real project. Let’s look at the two phases of this so called project: Moving the data from Couchbase to MongoDB Updating the application code to use

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

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)

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.

Overview

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.

Overview

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...)

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...)

Downloading JRockit and Java SE 6 from MOS

Oracle no longer posts updates of Java SE 6 and JRockit to its public download sites.

If you have a support contract you can download new updates from MOS.

You can locate the Java SE 6 downloads in this note “All Java SE Downloads on MOS (Doc ID 1439822.1)”.

(more...)

Java GC in Numbers – Compressed OOPs

Compressed OOPs (OOP – ordinary object pointer) is a technique reducing size of Java object in 64 bit environments. HotSpot wiki has a good article explaining details. Downside of this technique is what address uncompressing is required before accessing memory referenced by compressed OOPs. Instruction set (e.g. x86) may (more...)