Bert Ertman
Fellow at Luminis in the Netherla
                                 nds
JUG Leader for NLJUG and a Java
                                  Champion
     @bertertman



Paul Bakker
Senior developer at Luminis Tech
                                nologies
     @pbakker
Who is this talk
     for?
You are using old school
Spring and wonder how to
move forward
Java EE seems to be hot again,
should you jump on this
train?
You love the J2EE Design and
Development book; but is it
still actual?
Why listen to us?


         d endless         ..worked
We’ve ha
                       extensively with
   Ja va EE vs.
                      J2EE, Spring and
      Spring
                       modern Java EE
  dis cussions...


..not employed by         ..and we’re no
  an application           Rod Johnson
   server vendor          groupies either
some disclaimers:

Not looking for another holy war
No shootout
No silver bullets
Why migrate?

                        Spring is
                       proprietary
                       technology
Upgrading from
old school Spring
 requires a lot of
  work anyway
                     Why not take it to
                      the standard?
This m ight have been competitive in the past...
But now we want THIS!
Let’s get



a couple of misunderstandings



             out of the way



          first...
Isn’t Java EE too fat?

Startup times with application deployed
  JBoss AS 7 ~2 seconds
  Glassfish V3 ~4 seconds
  Tomcat 6 + Spring ~4 seconds
Java EE 6 WAR file < 100kb
Isn’t Java EE too fat?

Startup times with application deployed
  JBoss AS 7 ~2 seconds
  Glassfish V3 ~4 seconds
                         Our favorite quote:
  Tomcat 6 + Spring ~4 seconds
Java EE 6 WAR file < 100kb in the Java EE spec
                         “Nowhere
                           does it say that Java EE
                               servers should be heavy
                                 weight and slow...”
Isn’t Java EE
  supposed to be evil?

Based on 2004 rhetorics

Ever heard of the fable of the tortoise and
the hare?
But I need dependency
         injection?

Java EE 6 introduced CDI
  More powerful,
  contextual DI model
  Makes the platform
  extensible in a
  standard way
But I must have AOP!

    Really?
You love getting
  your code all
                     Or are you just
asymmetric and
                    using AOP light
  unreadable?
                   a.k.a. Spring AOP
                     a.k.a. (Java EE)
                       Interceptors?
Can I still do unit
       testing?

It took a while to get
 there, but yes Java EE
 supports testing as well
do I need heavy tooling?
NO!

do I need heavy tooling?
Ca pabilities comparison
                               Spring                            JavaEE
Capability
  Dependency                                                            CDI
                             Spring Container
   Injection
                                                                         EJB
  Transactions               AOP / annotations

                                                                         JSF
 Web framework                Spring Web MVC

                                                                    Interceptors
       AOP             AspectJ (limited to Spring beans)


                                     JMS                             JMS / CDI
    Messaging

                                                                          JPA
    Data Access        JDBC templates / other ORM / JPA

   RESTful Web                                                         JAX-RS
                            Spring Web MVC (3.0)
     Services
                                                                    Arquillian *
 Integration testing        Spring Test framework
                                                                                              tion
                                                           * Not part of the Java EE specifica
Apparently,



it can all be done using



plain vanilla light weight



      Java EE
rm -Rf spring*
Sure it would be
fun, but not very
    realistic
We need a recipe that
 moves us forward
    step by step
Old school Spring app

lots of complex XML, no annotations
old / outdated ORM solution
  JDBC Templates, Kodo, Toplink, etc.
deprecated extension based Web MVC
(SimpleFormController, etc.)
Migration path
1. Upgrade Spring version
2.Replace old frameworks
   (ORM, web framework)
   within Spring
3.Run Spring and Java EE
   container side by side
4.Replace Spring entirely
5.Remove Spring container
Migration path
1. Upgrade Spring version
2.Replace old frameworks
   (ORM, web framework)
   within Spring
3.Run Spring and Java EE
   container side by side
4.Replace Spring entirely
5.Remove Spring container
Upgrade Spring version

Upgrade Spring runtime (replace JAR files)
No code / configuration changes
Migration path
1. Upgrade Spring version
2.Replace old frameworks
   (ORM, web framework)
   within Spring
3.Run Spring and Java EE
   container side by side
4.Replace Spring entirely
5.Remove Spring container
replace old frameworks
                                                  within Spring
presentaton
   layer



                            Web MVC

                              @AutoWired
business




                       Spring beans
 layer




                                                     Tasks

                      @AutoWired      @AutoWired
Data / Integration




                                   Spring JDBC
      layer




                     Kodo                          JMS beans
                                    Templates
replace old frameworks
                                                  within Spring
presentaton
   layer



                           Web MVC

                             @AutoWired
business




                      Spring beans
 layer




                                                     Tasks

                      @AutoWired      @AutoWired
Data / Integration




                                   Spring JDBC
      layer




                     JPA                           JMS beans
                                    Templates
replace old frameworks
                                                  within Spring
presentaton
   layer



                             JSF

                             @AutoWired
business




                      Spring beans
 layer




                                                     Tasks

                      @AutoWired      @AutoWired
Data / Integration




                                   Spring JDBC
      layer




                     JPA                           JMS beans
                                    Templates
replace old frameworks
                                                  within Spring
presentaton
   layer



                             JSF
                                                   Don’t touch Spring
                             @AutoWired             specific APIs yet
business




                      Spring beans
 layer




                                                         Tasks

                      @AutoWired      @AutoWired
Data / Integration




                                   Spring JDBC
      layer




                     JPA                              JMS beans
                                    Templates
W hat about Spring APIs we
don’t want to change yet?

   Jdbc Templates
   REST Templates
   Task Scheduling
   etc.
Migration path
1. Upgrade Spring version
2.Replace old frameworks
   (ORM, web framework)
   within Spring
3.Run Spring and Java EE
   container side by side
4.Replace Spring entirely
5.Remove Spring container
Using Spring and Java EE
      side-by-side

Disclaimer 1: this is just to give an idea, this
is not a production ready framework!


 Disclaimer 2: this is a migration path. Not
 the way you should build your next
 application...
Spring application
Servlet Container

  myapp.war
                       Spring container
    TX manager




                       ORM          Spring	
  
                                     beans
                 AOP


                                    Spring	
  
                                     beans
Java EE application
Java EE 6 application server
   CDI / EJB container

                                                  myapp.war
    TX manager




                             Interceptors
                  Security




                                            JPA
                                                  CDI	
  beans
                                                  Session	
  beans
Mixed
Java EE 6 application server

   CDI / EJB container
                                                  myapp.war
                                                   CDI	
  beans
                                                   Session	
  beans
    TX manager




                            Interceptors
                 Security




                                            JPA                   Spring


                                                   TX manager
                                                                            Spring	
  




                                                                      ORM
                                                                AOP
                                                                             beans
                                                                            Spring	
  
                                                                             beans
run Spring within
                                                    Java EE container
presentaton
   layer



                               JSF

                               @AutoWired
business




                                                        f
                     Spring beans                d stuf
 layer




                                              Ad
                                                here...
                                                              Tasks

                        @AutoWired
Data / Integration




                                     Spring JDBC
      layer




                      JPA                                   JMS beans
                                      Templates
add Java EE code
                                                    keep old Spring code
presentaton
   layer



                               JSF

                               @AutoWired
                                               @Inject
business
 layer




                     Spring beans        EJB       CDI          Tasks

                        @AutoWired                  @Inject
Data / Integration




                                     Spring JDBC
      layer




                      JPA                                     JMS beans
                                      Templates
Dependency Injection
Spring already supports
JSR-330
Use @Inject anywhere you use
@AutoWired
CDI could be almost a drop-in
replacement for Spring DI
  but opens up much more
  powerful options
Encapsulate Spring with
         CDI

 Write a CDI extension that
  bootstraps the Spring
  container
  looks up Spring Beans in the
  Spring container and
  publish in CDI context
The Spring DAO
JSF / CDI bean




                 Here we don’t
                 want to know
                 about Spring
CDI extension example




https://github.com/paulbakker/migrating-spring-to-javaee
Migration path
1. Upgrade Spring version
2.Replace old frameworks
   (ORM, web framework)
   within Spring
3.Run Spring and Java EE
   container side by side
4.Replace Spring entirely
5.Remove Spring container
presentaton
   layer
                                                entirely replace Spring

                               JSF

                               @AutoWired
                                               @Inject
business




                     Spring beans        EJB       CDI
 layer




                                                                Tasks

                        @AutoWired                  @Inject
Data / Integration




                                     Spring JDBC
      layer




                      JPA                                     JMS beans
                                      Templates
presentaton
   layer
                                            entirely replace Spring

                                 JSF

                                 @Inject
                                           @Inject
business




                           EJB             CDI             EJB Timers
 layer




                       @Inject                   @Inject
Data / Integration




                                   Spring JDBC
      layer




                     JPA                                     MDB
                                    Templates
The TX layer

Migrate Spring TX and DAOs to EJB
The TX manager is in the app server
An EJB is transactional by default
EJB has JPA integration
Come on, are you telling me EJBs are cool now?




                   You bet!

                                  Just like
   EJBs are just              Spring beans,
    container                   but without
    managed                    the container
      POJOs                   configuration
The Spring DAO
The Java EE alternative




     btw -
   this is an
     EJB! :)
Dealing with lazy loading
Many Spring apps use the Open-
EntityManager-In-View pattern
EJB has the Extended Persistence
Context
LazyInitializationException
Fixing lazy loading
Detached entities

Spring DAOs are stateless (all singletons)
Load > edit > save needs a merge
With an Extended PU we don’t
Migration path
Template addict?


Hooked to JDBC Templates!?

           Hmm, let’s start
          the old discussion
           whether or not to
              use ORM...

         Phase 1: denial

         Phase 2: migrate ;-)
Using JD BC Templates

1. Can b e injected with simple
   Producer method
2.It is n ot relying on Spring
   container
3.some extra    dependencies though
Template producer example
Migration path
1. Upgrade Spring version
2.Replace old frameworks
   (ORM, web framework)
   within Spring
3.Run Spring and Java EE
   container side by side
4.Replace Spring entirely
5.Remove Spring container
Removing Dependencies
Our classpath just has to
contain APIs, no framework
classes
From ~40 dependencies to just:
What about testing?




Spring is pretty good at this



        Java EE was not
How to test this?
CDI alternatives
What about
 JPA code?
Ar quillian

Create micro deployments
      using an API

    Run tests in real containers
Arquillian example
Wrap up
Is it all worth it?




blissful ignorance or painful reality ?!
Is there life after Spring?

 We believe that there is always
 room for innovation
   Ideally through Open Source
 When it flies, bring it back to
 the spec!
Other sessions of interest
Arquillian: The
Extendable Enterprise Test
                             Introducing Contexts and
Platform (24121)
                             Dependency Injection 1.1
Beginning Java EE 6          (22480)
(23421)
                             Java EE 6: The Cool Parts
CDI Today and Tomorrow       (21641)
(19941)
                             Java EE and Spring/MVC
Enterprise JavaBeans         Shoot-out (24161)
Technology 3.2 (23180)
                             Rethinking Best Practices
Hacking Java EE: CDI         with Java EE 6 (21622)
Extension Writing n00b to
l33t (23805)
contact us:
Bert Ertman
bert.ertman@lum
                inis.eu
Paul Bakker
paul.bakker@lum
                inis.eu

JavaOne 2011: Migrating Spring Applications to Java EE 6

  • 2.
    Bert Ertman Fellow atLuminis in the Netherla nds JUG Leader for NLJUG and a Java Champion @bertertman Paul Bakker Senior developer at Luminis Tech nologies @pbakker
  • 3.
    Who is thistalk for? You are using old school Spring and wonder how to move forward Java EE seems to be hot again, should you jump on this train? You love the J2EE Design and Development book; but is it still actual?
  • 4.
    Why listen tous? d endless ..worked We’ve ha extensively with Ja va EE vs. J2EE, Spring and Spring modern Java EE dis cussions... ..not employed by ..and we’re no an application Rod Johnson server vendor groupies either
  • 5.
    some disclaimers: Not lookingfor another holy war No shootout No silver bullets
  • 6.
    Why migrate? Spring is proprietary technology Upgrading from old school Spring requires a lot of work anyway Why not take it to the standard?
  • 7.
    This m ighthave been competitive in the past...
  • 8.
    But now wewant THIS!
  • 9.
    Let’s get a coupleof misunderstandings out of the way first...
  • 10.
    Isn’t Java EEtoo fat? Startup times with application deployed JBoss AS 7 ~2 seconds Glassfish V3 ~4 seconds Tomcat 6 + Spring ~4 seconds Java EE 6 WAR file < 100kb
  • 11.
    Isn’t Java EEtoo fat? Startup times with application deployed JBoss AS 7 ~2 seconds Glassfish V3 ~4 seconds Our favorite quote: Tomcat 6 + Spring ~4 seconds Java EE 6 WAR file < 100kb in the Java EE spec “Nowhere does it say that Java EE servers should be heavy weight and slow...”
  • 12.
    Isn’t Java EE supposed to be evil? Based on 2004 rhetorics Ever heard of the fable of the tortoise and the hare?
  • 13.
    But I needdependency injection? Java EE 6 introduced CDI More powerful, contextual DI model Makes the platform extensible in a standard way
  • 14.
    But I musthave AOP! Really? You love getting your code all Or are you just asymmetric and using AOP light unreadable? a.k.a. Spring AOP a.k.a. (Java EE) Interceptors?
  • 15.
    Can I stilldo unit testing? It took a while to get there, but yes Java EE supports testing as well
  • 16.
    do I needheavy tooling?
  • 17.
    NO! do I needheavy tooling?
  • 18.
    Ca pabilities comparison Spring JavaEE Capability Dependency CDI Spring Container Injection EJB Transactions AOP / annotations JSF Web framework Spring Web MVC Interceptors AOP AspectJ (limited to Spring beans) JMS JMS / CDI Messaging JPA Data Access JDBC templates / other ORM / JPA RESTful Web JAX-RS Spring Web MVC (3.0) Services Arquillian * Integration testing Spring Test framework tion * Not part of the Java EE specifica
  • 19.
    Apparently, it can allbe done using plain vanilla light weight Java EE
  • 20.
  • 21.
    Sure it wouldbe fun, but not very realistic
  • 22.
    We need arecipe that moves us forward step by step
  • 23.
    Old school Springapp lots of complex XML, no annotations old / outdated ORM solution JDBC Templates, Kodo, Toplink, etc. deprecated extension based Web MVC (SimpleFormController, etc.)
  • 24.
    Migration path 1. UpgradeSpring version 2.Replace old frameworks (ORM, web framework) within Spring 3.Run Spring and Java EE container side by side 4.Replace Spring entirely 5.Remove Spring container
  • 25.
    Migration path 1. UpgradeSpring version 2.Replace old frameworks (ORM, web framework) within Spring 3.Run Spring and Java EE container side by side 4.Replace Spring entirely 5.Remove Spring container
  • 26.
    Upgrade Spring version UpgradeSpring runtime (replace JAR files) No code / configuration changes
  • 27.
    Migration path 1. UpgradeSpring version 2.Replace old frameworks (ORM, web framework) within Spring 3.Run Spring and Java EE container side by side 4.Replace Spring entirely 5.Remove Spring container
  • 28.
    replace old frameworks within Spring presentaton layer Web MVC @AutoWired business Spring beans layer Tasks @AutoWired @AutoWired Data / Integration Spring JDBC layer Kodo JMS beans Templates
  • 29.
    replace old frameworks within Spring presentaton layer Web MVC @AutoWired business Spring beans layer Tasks @AutoWired @AutoWired Data / Integration Spring JDBC layer JPA JMS beans Templates
  • 30.
    replace old frameworks within Spring presentaton layer JSF @AutoWired business Spring beans layer Tasks @AutoWired @AutoWired Data / Integration Spring JDBC layer JPA JMS beans Templates
  • 31.
    replace old frameworks within Spring presentaton layer JSF Don’t touch Spring @AutoWired specific APIs yet business Spring beans layer Tasks @AutoWired @AutoWired Data / Integration Spring JDBC layer JPA JMS beans Templates
  • 32.
    W hat aboutSpring APIs we don’t want to change yet? Jdbc Templates REST Templates Task Scheduling etc.
  • 33.
    Migration path 1. UpgradeSpring version 2.Replace old frameworks (ORM, web framework) within Spring 3.Run Spring and Java EE container side by side 4.Replace Spring entirely 5.Remove Spring container
  • 34.
    Using Spring andJava EE side-by-side Disclaimer 1: this is just to give an idea, this is not a production ready framework! Disclaimer 2: this is a migration path. Not the way you should build your next application...
  • 35.
    Spring application Servlet Container myapp.war Spring container TX manager ORM Spring   beans AOP Spring   beans
  • 36.
    Java EE application JavaEE 6 application server CDI / EJB container myapp.war TX manager Interceptors Security JPA CDI  beans Session  beans
  • 37.
    Mixed Java EE 6application server CDI / EJB container myapp.war CDI  beans Session  beans TX manager Interceptors Security JPA Spring TX manager Spring   ORM AOP beans Spring   beans
  • 38.
    run Spring within Java EE container presentaton layer JSF @AutoWired business f Spring beans d stuf layer Ad here... Tasks @AutoWired Data / Integration Spring JDBC layer JPA JMS beans Templates
  • 39.
    add Java EEcode keep old Spring code presentaton layer JSF @AutoWired @Inject business layer Spring beans EJB CDI Tasks @AutoWired @Inject Data / Integration Spring JDBC layer JPA JMS beans Templates
  • 40.
    Dependency Injection Spring alreadysupports JSR-330 Use @Inject anywhere you use @AutoWired CDI could be almost a drop-in replacement for Spring DI but opens up much more powerful options
  • 41.
    Encapsulate Spring with CDI Write a CDI extension that bootstraps the Spring container looks up Spring Beans in the Spring container and publish in CDI context
  • 42.
  • 43.
    JSF / CDIbean Here we don’t want to know about Spring
  • 44.
  • 45.
    Migration path 1. UpgradeSpring version 2.Replace old frameworks (ORM, web framework) within Spring 3.Run Spring and Java EE container side by side 4.Replace Spring entirely 5.Remove Spring container
  • 46.
    presentaton layer entirely replace Spring JSF @AutoWired @Inject business Spring beans EJB CDI layer Tasks @AutoWired @Inject Data / Integration Spring JDBC layer JPA JMS beans Templates
  • 47.
    presentaton layer entirely replace Spring JSF @Inject @Inject business EJB CDI EJB Timers layer @Inject @Inject Data / Integration Spring JDBC layer JPA MDB Templates
  • 48.
    The TX layer MigrateSpring TX and DAOs to EJB The TX manager is in the app server An EJB is transactional by default EJB has JPA integration
  • 49.
    Come on, areyou telling me EJBs are cool now? You bet! Just like EJBs are just Spring beans, container but without managed the container POJOs configuration
  • 50.
  • 51.
    The Java EEalternative btw - this is an EJB! :)
  • 52.
    Dealing with lazyloading Many Spring apps use the Open- EntityManager-In-View pattern EJB has the Extended Persistence Context
  • 53.
  • 54.
  • 55.
    Detached entities Spring DAOsare stateless (all singletons) Load > edit > save needs a merge With an Extended PU we don’t
  • 56.
  • 57.
    Template addict? Hooked toJDBC Templates!? Hmm, let’s start the old discussion whether or not to use ORM... Phase 1: denial Phase 2: migrate ;-)
  • 58.
    Using JD BCTemplates 1. Can b e injected with simple Producer method 2.It is n ot relying on Spring container 3.some extra dependencies though
  • 59.
  • 60.
    Migration path 1. UpgradeSpring version 2.Replace old frameworks (ORM, web framework) within Spring 3.Run Spring and Java EE container side by side 4.Replace Spring entirely 5.Remove Spring container
  • 61.
    Removing Dependencies Our classpathjust has to contain APIs, no framework classes From ~40 dependencies to just:
  • 62.
    What about testing? Springis pretty good at this Java EE was not
  • 63.
  • 64.
  • 65.
  • 66.
    Ar quillian Create microdeployments using an API Run tests in real containers
  • 67.
  • 68.
  • 69.
    Is it allworth it? blissful ignorance or painful reality ?!
  • 70.
    Is there lifeafter Spring? We believe that there is always room for innovation Ideally through Open Source When it flies, bring it back to the spec!
  • 71.
    Other sessions ofinterest Arquillian: The Extendable Enterprise Test Introducing Contexts and Platform (24121) Dependency Injection 1.1 Beginning Java EE 6 (22480) (23421) Java EE 6: The Cool Parts CDI Today and Tomorrow (21641) (19941) Java EE and Spring/MVC Enterprise JavaBeans Shoot-out (24161) Technology 3.2 (23180) Rethinking Best Practices Hacking Java EE: CDI with Java EE 6 (21622) Extension Writing n00b to l33t (23805)
  • 72.
    contact us: Bert Ertman bert.ertman@lum inis.eu Paul Bakker paul.bakker@lum inis.eu