The Spring Experience

Last week, I attended The Spring Experience in Miami. The event was a fantastic, in-depth introduction to the Spring Application Framework, a lightweight application framework that makes J2EE software development and deployment easier.

I won a pass to the show at a recent NEJUG meeting. Jay Zimmerman of No Fluff Just Stuff, which ran the show, donated the pass to the JUG. My employer, CentrePath, kindly paid my travel expenses.

The show was run by No Fluff Just Stuff. Based on my experience at this show, I would recommend that anyone who wants to spend a few days really learning technology should attend a No Fluff session.

Here are my fairly raw notes.

2005-12-07: Spring Experience day 1

Airport
My flight arrived at MIA a little early. The pilot announced that we would be delayed getting to the gate because of a "security incident." My phone rang--it was my wife calling to tell me about the a little problem that was currently being played out. Here's my own low quality photo, taken with my PDA from my seat on my plane as it drove by on the way to our new gate:

Dinner

• SourceBeat.com-good Spring blogs

Keynote: Rod Johnson

• Founder of Spring & Interface 21
  

• Says lots of clients in banking, government, defense-thus it has been proven
  

• Goal: simplify enterprise software development
  

• Non-invasive framework
  

• J2EE w-o EJB
  

• 2.0M1 released
  

  • simpler more extensible XML config
    enhanced integration w- AspectJ
    

    • use AspectJ pointcut expression lang w- Spring AOP

  • CommonJ TimerManager for scheduled tasks
    

  • msg driven POJOs
    

  • et al
    

• Things they got right
  

  • POJO model
    

  • simplify w-o sacrificing power
    

  • Apache license
    

• Nice demo of XML code completion in Idea
  

• Non-invasive POJO programming model-framework doesn't overtakn your app code-framework can change (eg Spring 2.0) but your code still works
  

• Demo: JPetStore on Spring 2.0M1, w- no changes from app on prev Spring release
  

• 2.0 final-March 2006
  

2005-12-08: Spring Experience day 2

Spring Fundamentals: Rod Johnson

• Aims
  

  • POJOs
    

  • Enterprise services in a declarative, non-invasive way
    

  • eg: POJOs transactional w-out transactional APIs
    

• POJO dev
  

  • not subject to unusual contracts, eg EJB 1 or 2 home inrerface, etc.
    

  • not bound to any environment
    

  • testable
    

• Apply services to POJOs declaritively
  

  • decouple app from environment-enables reuse
    

• Enabling tech
  

  • IoC/DI-inversion of control/dependency injecton
    

  • AOP
    

  • portable service abstractions
    

• Lightweignt container
  

  • facilitates POJO-based app dev at all tiers
    

  • within any env
    

• Sophisticated object factory
  

  • your biz obj's+config metadata+spring->fully config'd POJO
    

• Enablers
  

  • component=POJO
    

  • testable in isolation
    

  • minimal depend's->easily mocked
    

• Bene's
  

  • portability
    

  • leverage: decoupled from infrastructure
    

• AOP
  

  • modularizes behavior that would otherwise be scattered over diff methods
    

• Modules
  

  • Java/J2EE support lib's focused on ease of use, w-o sacrificing power
    

  • data access abstraction
    

  • transaction mgmt abstraction
    

  • remoting: RMI, IIOP, Axis, etc.
    

  • JMX support: expose any POJO for mgmt
    

  • JMS support: msg driven POJOs in 2.0
    

  • DI facilitates unit testing-org.springframework.test
    

  • MVC web framework
    

• IOC/DI
  

• Scoping
  

  • 2.0
    

  • per session, request, or arbitrary
    

  • testable because no need to access APIs, eg HTTPSession
    

  • ;
    

• Scripting support
  

  • bean can be impl'd in script lang, eg Groovy
    

  • hot reload
    

• AOP
  

• Template pattern
  

  • Form of IoC
    

  • moves control into framework
    

  • solves common prob's: resource acq/release, exc translation, etc.
    

  • Avoids TCFTC: try/catch/finally{try/catch}
    

  • Common exception hierarchy-exceptions are non-checked, so code is easier to write
    

• Work w- Spring
  

  • program to interfaces
    

  • focus on domain obj's
    

• Avoid
  

  • pull configuration
    

  • Singleton pattern
    

  • dependence on Spring APIs
    

  • writing pointless code, eg JNDI lookups
    

• J2EE != EJB
  

• My Q: Is it aadvisable to use a traditional container such as JBoss? his A: Don't use JBoss for msg beans-use ActiveMQ
  

Real World JDBC w- Spring: Rod Johnson & Thomas Risberg

• (see slides)
  

• About using JDBC templates when OR mapping is too slow
  

• RowMappper.mapRow()-a way to define how obj's are instantiated from ResultSets
  

• LobHandler-portable Large Obj Binary stuff
  

• Named parameters are much easier to read & maintain than ?s
  

Expert panel

• Anemic domain obj's
  

  • not solved in 2.0 because it's hard to DI obj's that aren't instantiated by Spring, eg new or OR)
    

  • Aspects can help
    

• Recommend not overusing annotations
  

  • keep config external
    

  • annotations force class-scope control; you lose instance-scope control
    

• Rails
  

  • a lang
    

  • convention is more important than configuration
    

Test driven dev w- Spring and Hibernate: Matt Raible

• Recommendation: start a blog, use Roller (Here it is, Matt!)
  

• (See slides)
  

• Selenium-a web app test tool that invokes and runs in your browser-thoughtworks.com
  

• Hibernate: new users use XDoclet to gen .hbm.xml files
  

• Dumbster-eg, fake SMTP server for unit tests
  

• There's an Eclipse plugin that autogen's equals, hashcode, & toString
  

• Use spring-mock
  

• Use DBUnit to establish & reset data for unit tests
  

• Use EasyMock
  

Enterprise app mght w- Spring: Rob Harrop

• (see slides)
  

• Java 5 VM param to start JMX: -Dcom.son.management.javaremote
  

• Java 5 VM includes JConsole (J2SE 5.0 Monitoring & Management Console)
  

• Use aspects to separate instrumentation from real code, then expose it through JMX
  

• MC4J: an alternate open source mgmt console
  

• Hibernate can be exposed as nice set of mgmt stuff
  

• HP OpenView is a JMX client
  

• Spring's Architecture-Juergen Hoeller
  

• J2EE app framework
  

• Not monolithic-loosely coupled subsystems
  

• Or think of Spring as a library
  

• Nature

  • Broad but thin
    

  • complementing prod's are specific and deep, eg OR tools, distributed transaction coordinators, web service engines, J2EE servers
    

• Easier to update your app w- Spring as a llb, than to update your J2EE container, which is system software
  

Managing & monitoring Spring based apps: Dieter Dirkes

• SpringStatelessSessionBeanFactory-to get SLSBs w-o, eg, JBoss
  

Metadata: Rod, Jourgen, Rob, Adrian

• Use 1 Spring config file per module
  

• FreeMarker: like JSP, but easier & better
  

• Mesh is good for applying CSS
  

• Recommend JAXB for XML->DB, with Java biz obj's as the translation layer
  

• Clustering for scalability
  

  • Hibernate+
    

  • SFSBs don't scale well
    

  • SLSBs, MsgBeans scale well
    

  • use Cisco load balancer HW
    

• Fortune 500 co's want to move away from big fat containers. Eg, BEA is supporting Spring because their big cust's demand lt.
  

• If an annotation makes sense in the domain's context, it's OK. If it specifies some binding to a framework or environment, it's bad.
  

Why this conference is so great

• I chatted w- Rod Johnson, inventor of Spring
  

• I had lunch w- Craig Walls, author of Spring in Action
  

• I met Mike Clark, potential employee (Mike, if you see this, look me up. I lost your email address.)

• I drank beer with Chris Richardson, author of upcoming book POJOs in Action. He described a successful project w- goals similar to ours: gradually replace a prod's infrastructure w- Spring-based J2EE.
  

2005-12-09: Spring Experience day 3

Enterprise Integration: Using JMX and JCA: Juergen Hoeller

• (see slides)
  

• Use transactions to define delivery behavior. Eg, if send fails w-in transaction, transaction rolls back and acts as if transaction never occurred.
  

Service oriented Spring: Craig Walls

• (see slides)
  

• EAI=enterprise architecture integration
  

• His demo uses Jencks as interface to ActiveMQ
  

• Demo2 uses Lingo for true POJO msg queueing. Lingo: a way of exposing msg-based services as if they were local method calls. A CodeHaus project.
  

• ESB=enterprise service bus
  

• SEDA=staged event driven architecture, eg, there is a queue
  

• JBI=Java Business Integration
  

• BPEL="bee-pull"
  

• PXE="pixie"
  

• Craig: leaving his employer on Mon. Has telecom background. Looking for work?
  

• Examples source code: www.habuma.com/SOS.zip
  

Breaks

The breaks were harsh. I got a chance to walk through the hotel's pool area to take a look at the pools I didn't have time to use (more low quality PDA camera shots):

Just past the pool area, I had the opportunity to enjoy the view of the beach I didn't have time to use:




Expert panel


Spring & web services: Alef Arendsen

• (see slides)
  

• Spring-WS looks like a valid way to do WS.
  

OR persistence: Jim Wall (Oracle/TopLink)

• (see slides)
  

• Not really Sprng-focused on EJB3
  

• JPA=Java Persistence API, a JSR for POJO persistence
  

• Dali: Eclipse plugin that helps you build OR mapping file
  

Dinner notes

• Mraible@virtuas.com: free book after 6:00am tomorrow

Keynote: Adrian Colyer

• Aspects define rules & policies


• independent of the problem domain, so don't encode directly in domain model (separation of concerns)
  

• Point cut=defines where the annotation applies
  

• can be used to enforce code standards, eg only use Spring to access JDBC-desigh level assertions
  

• (my example: add time measurement instrumentation to specified methods, or add temporary debug tracing)
  

• (like advice in Lisp-Defadvice (but instead of hardcoded function name, jou define a pointcut)
  

• Based on CLOS metadata
  

Case Study: French Tax Authority

• (see slides)
  

• Parameters
  

  • 34m tax payers, 3 yrs of history
    

  • 25k transactions/h
    

  • 25k digital sig's/h
    

  • 40k fiscal account consultations/h
    

  • <1s>
    

• All FOS exept Oracle
  

  • JBoss-only for MDBs, which were used only for logging-wouldn't need JBoss at all now w- Spring msg POJOs
  
  
• Problems and goals soond very similar to those of Mag


• DBUnit-helps test w-o real DB back end (?)


• ONE JVM-and all that performance & scalability