Java Tales from a Trading Desk

I've moved to WordPress

2005-12-22T13:49:00.000+00:00

I'm now blogging here.

FIT everywhere

2005-08-24T08:43:00.000+01:00

XPlanner - Could not execute query

2005-08-13T19:45:00.000+01:00

Have seen this a few times now, anyone got any ideas?

javax.servlet.jsp.JspTagException: net.sf.hibernate.JDBCException: Could not execute query at com.technoetic.xplanner.tags.db.UseBeansTag.doEndTag(UseBeansTag.java:133) at org.apache.jsp.index_jsp._jspService(index_jsp.java:83)

XPlanner Install Problems

2005-08-10T07:48:00.000+01:00

I got this stack trace after starting XPlanner on Tomcat 4.1.31 with MySQL:

javax.servlet.ServletException: java.lang.NullPointerException
at org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:495)
at org.apache.jsp.index_jsp._jspService(index_jsp.java:170)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:92)

This wiki suggests adding the database settings to resource/xplanner-custom.properties. But that didn't seem to help either :( I found a few other ideas to try here and here.

Nice review of Synergy here.

Agile good practices.

When faster is wrong, and slow is right

2005-07-29T09:11:00.000+01:00

Gosling has an interesting post on the Java sin() and cos() methods - Sun's bug detail.

Simian, and some wacky results

2005-07-26T12:46:00.000+01:00

What do you do when you see this from Simian?

<summary duplicatefilecount="2286" duplicatelinecount="229743" duplicateblockcount="16659" totalfilecount="3684" totalrawlinecount="1472768" totalsignificantlinecount="815444" processingtime="33657">

I suspect the answer is ...run

Agile 2005 Conference

2005-07-25T08:32:00.000+01:00

A colleague is blogging from the Agile 2005 conference this week.

TDD with Velocity/xmlunit

2005-07-21T21:26:00.000+01:00

A component I am working as part of a pricing system needed to generate HTML reports. A fellow consultant - from a rival consultancy :) - suggested I use Velocity. Velocity turned out to be an ideal fit for the problem I was solving. However, before I could write the code I needed to write the test - TDD. xmlunit was an ideal fit for the test cases - specifically the assertXpathEvaluatesTo method.

Evo - an old (1976) agile development methodology with 5 day iterations.

Know your software development tools

2005-07-19T08:15:00.000+01:00

As Kevin Johnson states in Extreme Programming Applied (page 174) "pairs will be stronger if they both discover the most efficient way to use their tools". He also notes that shortcut keys "minimize the friction caused by back seat drivers". Having migrated to IntelliJ a few weeks back (from Eclipse) I have to agree with Kevin's shortcut point - I can't learn the Idea's keymap fast enough.

Is this the start of Microsoft moving towards Open Source?

2005-07-12T12:18:00.000+01:00

OSDL boss hints at Microsoft collaboration

GridCache

2005-07-12T07:58:00.000+01:00

DataSynapse GridServer has the concept of a GridCache. Only problem with GridCache is that it has no locking, no transactions, and is not a distributed data repository. Maybe DataSynapse should consider integrating Blitz into their product. GigaSpaces on the other hand has a distributed cache, but doesn't (I could be wrong) offer all the grid services that DataSynapse offers. Maybe DataSynapse and Gigaspaces should merge :)

Unit Testing Database Access code

2005-07-12T07:41:00.000+01:00

HSQLDB appears to me to be a clean way of testing database access code. Just use the in-memory feature (jdbc:hsqldb:mem:), and implement your setUp method to create the appropriate tables, and tearDown to drop the tables.

Interesting to see that the Deutsche is listed as one of the openadaptor adopters - DrKW originally build openadaptor. Suprised no US investment banks are listed.

Came across Nagios today. Nagios is a monitoring program for host, service and networks. Nagios is fully pluggable, with the Nagios Exchange offering a selection of plugins. NSJS looks particularly interesting.

JBehave

2005-07-09T07:35:00.000+01:00

A colleague mentioned JBehave yesterday. Not knowing much about the project, I googled and came across Magpiebrain's blog. The Velvick Underground reflects on the BA's view of JBehave, as does the Agile Business Coach.

Damian has a good overview of Grid Computing, particularly relevant to the project I'm now on.

Another day, another client

2005-07-08T08:21:00.000+01:00

Having just finished working on a large Foreign Exchange (FX) project at a US client of Finetix, I'm now at a European bank (for Finetix) working on Grid Computing. The grid project is particular interesting for two of reasons:

DataSynapse is the application we are working on
Agile principles

About six years ago I wrote a grid computing framework and application. Unfortunately, neither saw the light of day. However the project did give me a good grounding in grid applications, so the new project I'm working on is very much a flash back to past experiences.

With regards to Agile, I'm a support of the Manifesto. This particular project has a number of ThoughtWork consultants attached to it, giving the project a real Agile flavour, not the more typical investment banking half baked Agile approach. Today out development environment is IntelliJ, Cruise Control with Emma, CheckStyle etc

Off-heap data management using memory mapped files (Java NIO)

2005-05-03T14:12:00.000+01:00

Tangosol

Bytecode of method variables

2005-04-29T10:05:00.000+01:00

Having installed the Bytecode Outline Eclipse plugin, and read the online instruction reference it would appear that the following two code extracts produce similar bytecode:

for (final java.util.Iterator iter = categories.iterator(); iter.hasNext();) {
final String s = (String)iter.next();
}

String s=null;
for (final java.util.Iterator iter = categories.iterator(); iter.hasNext();) {
s = (String)iter.next();
}

ALOAD appears to be used in both cases, implying that there is no performance advantage gained by moving the String outside the for loop

Why the SPARC architecture is dead

2005-04-01T07:22:00.000+01:00

The project (Java application, consisting of a number of server processes) I work on currently uses a Sun Fire 15K server in production (32G RAM, 12 CPU). Today we decided to test the same application on a Sun Fire v40z server (AMD Opteron 4 CPU, 32G RAM).

Running the same performance test on both server configurations, we found that the Opteron server was 3x faster than the SPARC server. Another group have done a similar server comparison but using there multi-process multi-thread C++ server and found a 3-4x speed improvement.

It's quite interesting to compare the cost of both systems - 15K vs V40z.

Given the performance improvement and cost savings, it's difficult to see where Sun is going with the SPARC architecture.

Oracle JDBC Drivers

2005-03-10T09:27:00.000+00:00

It's implied from the Oracle web site that if you are using JDK 1.4, then you should use ojdbc.jar. Anyone know if there are issues using classes12.zip (Oracle site implies classes12.zip is for JDK 1.2 and JDK 1.3) with JDK 1.4? A quick Google search return this issue.

Why can't Sun (Java) do this as well?

2005-03-10T07:23:00.000+00:00

Blog Day from the Microsoft BCL Team

TCP_NODELAY - Nagel algorithm

2005-02-15T09:17:00.000+00:00

The Nagel algorithm has the potential to influence performance - this article talks a bit about the algorithm

Who started my defunct processes

2005-02-03T15:18:00.000+00:00

/usr/proc/bin/ptree `ps -ef | grep -v ^\ \ \ \ root | awk '// {print $2}'` | less

Finally, OpenSolaris.org goes live

2005-01-26T07:12:00.000+00:00

Today we can only download the source to DTrace, but there is a hint of things to come from the home page; "Soon, you'll be able to download the OpenSolaris distribution.". With the OpenSolaris release we are finally seeing Sun developers blogging source code - Adam Leventhal and Bryan Cantrill are just two examples. Calvin Austin's recent leaving sun blog entry hinted at problems within Sun with regards to blogging source code - which is a shame since the Java 5.0 source has been available for some time. Hopefully soon we might actually being to see more JVM Sun bloggers in the same calibre as Adam and Bryan, together with a blogroll of JVM developers equivalent to the Solaris Kernal Developers.

Solaris Internal Links

2005-01-14T11:39:00.000+00:00

Load Averages Explained
Performance Analysis and Monitoring Using Hardware Counters
prstat
Solaris Internals and slides
Hows to check your box is running 64-bit: isainfo -kv
Check Solaris patch levels: showrev -p
LWP
Managing Thread Execution and Wait Times

A Comparative Study of Persistence Mechanisms

2005-01-06T13:12:00.000+00:00

An interesting article from Sun Labs. If anything, the conclusion is worth a read.

"Acceptable EJB performance seems unattainable at present unless dramatic changes are made to the application object model to avoid fine-grain objects when mapped to EJB. While this approach is now reflected in standard design patterns for EJB, the extra effort that it implies is disturbing from the overall application design perspective. In contrast, JDO manages to achieve reasonable performance at much lower impact on application design, while remaining agnostic to the nature of the external data store. Therefore, at this time, JDO would seem to offer the best overall persistence mechanism for demanding, object-oriented, applications. Note, however, that at the time of writing, a new specification for entity bean persistence [Sun04] was being proposed for EJB 3.0 that would bring it much closer to JDO in spirit."

MythTV

2005-01-06T07:12:00.000+00:00

Now this looks cool. All I need to do is fine time to install it on my Linux box.