Showing posts from September, 2009

Database sharding

Shared nothing instances



Java Round Robin Graphing

JBoss 5

Browse the JNDI tree view

In a browser:
Connect to http://localhost:8080
or http://localhost:8080/web-console
or http://localhost:8080/jmx-console

In the Web Console:
Open: System : JMX MBeans : jboss : jboss:service=JNDIView
In the third/last table click the 'Invoke' button on the list row

Or in the JMX Console:
Under the jboss section click on the 'service=JNDIView' link
In the third/last table click the 'Invoke' button on the list row

DO NOT click on jboss.deployment
and select 'id="jboss:service=JNDIView",type=Component'
It does not have the facilities to list the JNDI tree view.

Admin Console
Default username: admin, password: admin

Converting to JBoss 5 info:

JBoss 5 is strict in validating xml.

The persistence.xml needs to be changed from:

<?xml version="1.0" encoding="UTF-8"?>
<persistence-unit name="titan">
. . .


<?xml version="1.0" encodin…

JDBC debugging


* P6Spy most well known, not recently updated
* Craftsman Spy not recently updated
* JAMon (Java Application Monitor) comprehensive app monitor and API, includes JDBC/SQL
* JdbcProxy can emulate another JDBC driver to test the app without a database.
* LogDriver

Continuous Integration



XML - Russian Doll vs. Salami Slice vs. Venetian Blind

Hibernate configuration files and hibernate.cfg.xml perform the same configuration functions, if hibernate.cfg.xml exists it takes precedence over

The configurations can include Datastore, SessionFactory, Connection Pool, Transactions, and Cache Provider.

Much if not all of this can also be specified in the persistence.xml and the *-ds.xml.

Generally the persistence.xml specifies only the persistence unit name, jndi-name, mode (create, drop, etc.) for an EE application and everything in a standalone application.
Generally the *-ds.xml specifies the data source connection parameters, jdbc url, driver class, credentials, connection test parameter, provider type (Oracle, MySQL, etc.).
Generally the hibernate.cfg.xml specifies the others.

hibernate.cfg.xml is placed in WEB-INF/classes
persistence.xml is placed in META-INF in jar with entity beans

Hibernate Quickly

Eclipse Remote System Explorer Plugin

Like winscp for Eclipse:

Remote System Explorer (RSE)

• remote file systems through SSH, FTP or dstore agents (seamless editing of remote files including remote search and compare),
• remote shell access (compiling with error navigation),
• remote process handling through dstore agents, and remote debugging through CDT / gdb /

GC Tuning

Remote JConsole and VisualGC

To connect visualgc remotely you need to be running jstatd on the server to be monitored.

Create a jstatd.all.policy containing:

grant codebase "file:${java.home}/../lib/tools.jar" {

Set and export the JAVA_HOME environment property and start jstatd with:

nohup jstatd > jstatd.out 2>jstatd.err &

The default port is 1099.

Either get the pid from the server or start JConsole to get it.

In JConsole int Remote process enter server:port and a username and password if you set authentication to true below.

Ah yes, you will have to have started the Java process with the following environment (but should be using JConsole for monitoring and debugging anyway):

When JConsole starts, click on the VM Summary tab.

This shows you many details about the JVM including…

EE5 Web Service - Maven + Eclipse + JBoss 5

In Eclipse

Create the project:

File : New : Other : Maven Project
Uncheck create a simple project (skip archetype selection)
Click Next
Select Catalog: Internal
Double-click maven-archetype-webapp
Enter Group Id:
Enter Artifact Id: someName
Click Finish

Set the Java version:

Open the pom.xml
Add the following:

. . .

Create the artifacts:

Right click on the project name in Package Explorer
Select New : Source Folder
Enter src/main/java
Click Finish
Right click on the new source folder src/main/java
Select New : Package
Enter a new package name or structure
Right click on the new package name

DocBook format

DocBook XML is a library of standard XML tags you can use to write stylesheets for generating other output like HTML, PDF, etc.

Build DocBook XML in Eclipse

Diagnosing EE/System problems

Check the following: (order depends on issue)

- JConsole (memory, cpu utililzation, threads, deadlocks)
- JStack (blocking, locks, what are threads doing) or kill -3

- Load Balancer log
- Access Log
- Query Log
- GC log - been burned by this one twice
- Server logs (JBoss, server, error, etc.)
- Log4j logging latency - use async appenders

Virtualization issues (VMWare)
- OS scheduling latency
- Network latency
- Filesystem latency

OS stats
- top
- ntop
- iostats

External System Latency
- databases
- AD
- EMail
- Web Services
- network storage
- etc.

Import cert into Java keystore

from jdk.X.X.X/jre/lib/security
keytool -import -file some.cert -keystore cacerts
default password: changeit