Posts Tagged ‘J2EE’

Following the post on widely used DTDs, here is a list of some XSD (aka XML Schemas):

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

<weblogic-web-app xmlns="http://www.bea.com/ns/weblogic/weblogic-web-app" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.bea.com/ns/weblogic/weblogic-web-app http://www.bea.com/ns/weblogic/weblogic-web-app/1.0/weblogic-web-app.xsd">

<assembly xmlns="http://maven.apache.org/xsd/1.1.0/assembly" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/xsd/assembly-1.1.2.xsd http://maven.apache.org/xsd/1.1.2/assembly">

<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

Abstract

WebLogic offers you to specify a startup and/or a shutdown class for an application. Anyway, this feature is restrained to EARs, and is not available for applications deployed as WARs. For EARs, Oracle WebLogic Server’s documentation is complete and gives basic examples: Programming Application Life Cycle Events

Yet, sometimes you need such a class even for a WebApp. You have two ways to handle this case.

Solutions

Full Weblogic!

Base

The first solution is not elegant. Open WebLogic console, go to Startup And Shutdown Classes, then add the classes names of which main() methods will be run on startup and shutdown, let’s say JonathanWeblogicStartup. These classes must be available in WebLogic classpath, which is surely different from your application classpath, eg in a library $DOMAIN_HOME/lib/customized-weblogic.jar.
Advantage of this means: if your startup/shutdown class does not evoluate often, then write it once and forget, it will be OK. Unlike, you will have to manage different versions of the JAR on each release… I assume your exploitation team may get angry at playing with classpaths and lib folders 😀

Suggestion

To improve the basic solution (and avoid your exploitation guy burst in your office), I had the following idea, that I did not experiment, but that should work:

• Keep JonathanWeblogicStartup

• Create another class JonathanConcreteStartup, locate as a source in your application code.
• In JonathanStartup.main(), call JonathanConcreteStartup

This way,

1. You keep a unique JAR in classpath that you do not need to update and you can forget.
2. You can add, update or remove features in your very source code.
3. The exploitation teams does not become hateful at you.

Add a Listener

The second one requires a bit more work.

• Create a class implementing javax.servlet.ServletContextListener interface, let’s say MyLifecycleListener.
• Implement methods contextInitialized() and contextDestroyed().
• Edit your web.xml, add the following block:

    <listener>
          <listener-class>lalou.jonathan.MyLifecycleListener</listener-class>
      </listener>

• Rebuild and deploy. It should be OK

Recent history

BEA WebLogic 9.0, 9.1 and 9.2 were released from 2007: the main features were: a new console, WLST (WebLogic ScriptingTool), deployment plans, WebLogic Diagnostic Framework (WLDF), new security providers (RDBMS, SAML 1.1, etc.), JMS performance improvements, support of Java EE 4, JDK 5, Spring, OpenJPA, Kodo, etc.

Since this date, some events happened:

• Oracle bought Sun (2009)
• Oracle released WebLogic 10.3 (2008)
• Oracle bought BEA (2008)

WebLogic Server 10 General Features

• Developer productivity ehancements
  • JDK 6, Java EE 5
  • Support of EJB3 and JPA
  • BEA enhancements
• Web Services: more annotations, less XML
  • JAX-RPC Web Services Enhancements
  • JAX-WS 2.0 Web Services Implementation
• Misc:
  • Better administration console
  • Auto-Record of Admin Console actions as WLST scripts
  • Automatic JTA Transaction Recovery Service (TRS) migration
  • SNMP 3.0
  • Production Application Redeployment enhancements
  • Clustering – Unicast messaging (in addition to Multicast)

Programmer Perspective

• New persistence engine: TopLink
• OEPE (Oracle Entreprise Pack for Eclipse): sequence of tools and plugins for Eclipse: remote deployment, debugging,  editors for weblogic.xml and weblogic-application.xml, wizards, facets, Weblogic ClientGen, WSDLC and JAXB wizards
• Optimizations for Spring integration and certication
• Web 2.0:
  • Ajax / Dojo client support
  • Http publish / submit engine for collaborative applications:
    • Bayeux protocol
    • data exchange within applications over persistent connections
    • scalability for Dojo clients
• Ad-hoc tools for:
  • Oracle Database
  • Spring
  • JAX-WS webservices

Lightweight WebLogic Server

WebLogic 10 offers a light weight server:

• Install only “core” WebLogic server
• Optionally, startup other services (JDBC, EJB, JMS, etc.)
• FastSwap: modify classes without requiring redeployment.

Architect Perspective

Architects have to consider WebLogic as a complete suite, and not only WebLogic Server:

• Oracle RAC integration: Connectivity to RAC with load balancing, failover, transactions
• Enterprise Messaging with JMS: High performance and reliable JMS messaging engine “built-in”
• ActiveCache with Coherence*Web and EJB/JPA: Coherence Data Grid caching included and integrated
• Operations Automation: Tools for automating management of applications and servers
• Operations Insight: Tools for diagnosing problems in development and production
• Other features
  • Development tools: Choice of tools for developer productivity
  • Web Services: Enterprise Web Services for SOA
  • TopLink: Persist application data to stores with performance and productivity. It works in a way similar to Hibernate L2 cache.
  • Spring: Enable flexible choice of dev frameworks with same WebLogic QOS

Production and Support Perspective

WebLogic 10 provides a tool: JRockit Mission Control

• monitors more than 150 parameters:
• CPU
  • memory
  • leaks
  • latency spikes
  • threads
  • object references
  • JDBC connections
  • JMS
  • pools
  • clusters
  • configuration files
  • etc.
• allows to compare WebLogic domains
• Runtime Analyzer: runtime capture for offline analysis, Garbage Collector analysis, etc.

Coherence – ActiveCache

Coherence is the Data Grid offered by Oracle. It allows to store Java objects in memory, and share them between all instances. From a certain viewpoint, Coherence looks like the GigaSpaces.

Roadmap for Future WebLogic Releases

• Support of Java EE 6 (ratified by the community in last December)
• OSGi deployment
• More native integration for WebLogic Server – Coherence – Oracle Database
• JRockit Flight Recorder for constant record
• Virtualization
• More integration with Maven, Hudson and Cruise Control
• Shared Library: use the same JAR for many applications, rather than packing the same JAR in different EARs.
• On long term:
  • IDE
    • NetBeans to be oriented onto J2ME development
    • JDevelopper to remain Oracle strategic IDE
    • Contributions to Eclipse to go on
  • JRockit and Sun HotSpot JVMs to be merged.