multiple tomcat instance - single setup

running multiple tomcat by using a single catalina_base and catalina_home

this will make it easy to manage server management to use only one tomcat setup instance

download tomcat-6+ and unpack it.

and modify two configuration file under conf

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hibernate native id generator bug 3.2.4-ga

hibenate native id generator for mysql not working just update to 3.2.5

Caused by: java.sql.SQLException: No value specified for parameter 11
at com.mysql.jdbc.PreparedStatement.fillSendPacket(PreparedStatement.java:2212)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1724)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1596)
at org.apache.commons.dbcp.DelegatingPreparedStatement.executeUpdate(DelegatingPreparedStatement.java:101)
at org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:73)
at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:33)

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Clustering Acegi via JGroups (DistributedHashtable)

in my previous blog I suggest to use jms or caching for a distributable SessionRegistry
but I found a more simple solution JGroups -

DistributedHashtable :JGroups gives us such a perfect simple class to distributed maps.

• All read-only operations runs on local copies
• perfect merge strategies.
• easy implementation and configuration
• vs..

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DistributableEventPublisher for Spring via JGroups

Messaging is really easy through a single JVM. For a distributed environments JMS is strongly recommended. but for smaller and simple projects here is and example implementation via JGroups.
Usage

DistributableEventPublisher distributableEventPublisher=….
distributableEventPublisher.castEvent(TEXT_MESSAGE/XML/Serializable);

requirements:

• springframework 2+
• JGroups 2.6.1
• JUnit (for test)

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light-weight distributed messaging via JGroups

JGroups is a framework that provide seamless networking utilities for java/j2ee applications. As a light-weight alternative to JMS here is an example.

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JGroups Basics

JGroups is a basic networking api for java.It handles all networking issues for u with very complex configuration and simple interfaces.Here are some basic introduction for JGroups

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for <distributable/> j2ee application

no matter what size is your application distributable should be always under consideration. otherwise it becomes a full pain full reimplementation of whole application. yes reimplementation is always good but for developers it is always painful and for customers it is always very but very expensive.

here is some key points

Model extends Objects implements java.io.Serializable

Your model objects and communication objects should be Serializable. Do not forget serialization is the most important feature. it necessary for caching,messaging,storing,…

API replacements

Every instance should be aware of its copies in cluster. so you may need some api replacements like

Map->DistributedHashtable : nice seamless implementation from JGroups.

Cache->Distributable cache: (eg:EhCache,OSCache)

Observer,Listener>JMS Queues : for whole notifications in the cluster.

Timer->Quartz distributable scheduler

 

 

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Complete Apache 2.2-AJP Load Balance via mod_proxy

Complete guide for apache-http server load balancing via mod_proxy and some performance enhancements

required modules:

proxy_module
proxy_ajp_module
proxy_balancer_module

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