I have found – by accident really! – a very interesting presentation on SlideShare concerning the different leading Open Source Application Servers on the market.

This very solid evaluation is proposed by OpenLogic.

I have summarized parts of it below.

Goal of the presentation /

Help you choose which open source application servers to evaluate more thoroughly:

• JBoss
• GlassFish
• dm Server
• Geronimo
• Tomcat

Which open source application servers are your using or considering using /

J2EE Didn’t Fill the Need /

• EJB 2 is difficult to use
  • Many people consider it unnecessary difficult
  • Entity Beans were especially problematic
  • But even session beans earned bad reputations
• The Open Source community responds
  • OSS packages mitigating the problem
    • Hibernate instead of Entity Beans
    • Spring as a component model
  • They were very successful in the marketplace
• Many Spring/Hibernate applications
  • Required only Tomcat to run but also work in full app servers

When Tomcat Is Not Enough /

• Tomcat doesn’t support
  • JMS
  • EJBs
  • Other…
• Enterprises need integration
  • The more mature the app is, the more likely it is to be added
• Add-ons
  • It was possible to add things that Tomcat was missing
  • But this became a “build your own Frankenstein” exercise

Java Enterprise Edition in the Meantime /

• Weaknesses in EJB 2 model were recognized
• Work on new specification was completed
  • J2EE → JEE 5
  • EJB 2 → EJB 3
    • Entity Beans → JPA
• EJB 3
  • Simple annotation-based programming model
  • Not everybody adopted EJB 3
• JEE 6 will embrace modularity
  • Profiles, including web profile

Choices in 2007 /

• Use Spring
  • Start with full app server
  • Start with Tomcat, build from there
• Use EJB 3
  • Requires full app servers
• Full application server
  • Pros – everything you are likely to need, could use EJB
  • Cons – complexity, might use more resources then Tomcat
• Tomcat
  • Pros – small, simple, low resource usage
  • Cons – you might need to build your own app server, no EJB

OSGi /

• Started in 1999
  • Recently got a lot of exposure
  • In particular, R 4.1
    • JSR-294
• OSGi brings
  • Dependency management and modularity
  • Ability to load only parts it needs
• OSGi currently has a lot of mindshare

The central questions /

• Decisions, decisions
  • EJB 3 or Spring
  • Spring on dm Server or on J2EE/JEE server?
  • OSGi or not OSGi
  • Do I need EJB 2 compatibility?
  • In addition, there are many “old” considerations
• Servers are not “all inclusive”
  • EJB 3 apps won’t work on SpringSource dm Server or Tomcat

Assessment JBoss /

JBoss Thought Leadership Complete ecosystem Portal ESB BPM JBoss has history of innovation Pioneer of EJB 3 Seam Application Framework Web Beans OSGi Support in JBoss 5	JBoss for Developers Excellent customizability JMX-based, don’t deploy what you don’t need Seam is worth a look for developers JDK 6 with 4.2.3 and 5.0 GA JDK 5 compiled binaries work on both JDK 5 and JDK 6 JBoss IDE Eclipse-based JBoss Tools Free version (RHDS is paid version)
JBoss in Production Dependability Excellent clustering and failover capability Reliable in production Monitoring and deployment capabilities Not really oriented toward system administration out of the box Command line/file edit flavor of configuration GUI tools (Tomcat manager and JMX Console) are fairly basic Excellent 3rd party tools available for monitoring Hyperic GroundWork IT JON *	JBoss – Conclusions Strengths Mature, scalable and reliable Good support for J2EE and EJB 3 Seam framework Weaknesses Limited GUI-based configuration in open source version LGPL License may be a concern for ISV’s embedding app servers

Assessment SpringSource dm Server /

SpringSource dm Server Newcomer Released in April of 2008 GPL license Incorporates many mature components Spring Framework Tomcat Equinox dm Server users are very early adopters Different take on app server OSGi support No support for EJB No JMS out of the box	dm Server for Developers Server works well with Spring Framework IDE Spring IDE – IDE for Eclipse platform Support for NetBeans and IntelliJ OSGi support Resolves “dependency hell” But requires application migration to take advantage of it Supports Java 5 and 6
dm Server Thought Leadership OSGi-based Good OSGi implementation OSGi discussed a lot in their documentation No support for EJB No support for EJB 3 or old EJB 2 spec Spring offers similar functionality to Seam Which is somewhat more mature Although some of the Seam ideas might be somewhat more powerful Bijection	dm Server – Conclusions Strengths Support for Spring Framework Support for OSGi Weaknesses Newcomer No EJB Limited experience among workforce

Assessment Tomcat /

Tomcat First release (3.0.x) in 1999 Apache license Servlet container Lightweight server Used in many other app servers JBoss dm Server Geronimo	Tomcat – Conclusions Strengths Lightweight Well known and tested < li>Fast startup/deployment for development Weaknesses No support for EJB, JMS or almost anything else outside of “web side”
Tomcat in Development and Production Tomcat 6 supports Clustering Failover Widely used for both development and production Supported in most popular IDEs

Conclusions /

• App servers are not just about the JEE specs
• Make some high-level decisions before evaluation
  • Do I need EJB 2 compatibility?
  • Do I intend to follow EJB 3 and other industry standards?
  • Do I need something fast, lightweight, and easy to use?
  • Do I have a need for lifecycle management of server components (through OSGi)?
  • Do I need support for dynamic languages like Groovy and JRuby?
  • Am I an early adopter of new technology?

Recommendations /

• “I’m using EJBs and I’m conservative”
  • JBoss, GlassFish
• “I don’t need XA/JMS/EJB”
  • Tomcat, JBoss, GlassFish, dm Server
• “I’m using Spring”
  • Conservative – JBoss, Tomcat, GlassFish
  • Leading edge – dm Server
• “I need to embed an app server in my commercial code”
  • Tomcat, Geronimo
• “I use Spring heavily and I need OSGi”
  • I need it today and don’t need EJBs – dm Server
  • I need it soon and/or need EJBs – GlassFish, JBoss
• “I use Seam”
  • JBoss
• “I want ActiveMQ/Spring/Hibernate preinstalled”
  • Geronimo
• “I need dynamic language support”
  • Groovy/Grails – dm Server, JBoss, GlassFish
  • JRuby/Rails – GlassFish, Geronimo