Juergen Hoeller, Co-founder of the Spring Framework Project

If you programmed enterprise-java in the beginning of the millenium you probably struggled with Enterprise Java Beans (EJB's).
Juergen Hoeller did too.
Together with Rod Johnson he dared to question the sanity of the EJB-programming model and came up with a better alternative.

First Rod Johnson wrote the book "J2EE Design and Development" published in late 2002 which contained a prototype for a framework which tried to deflate the immensely complex and bewildering EJB-programming model.
Juergen Hoeller joined Rod Johnson's quest for simple programming with J2EE and together they wrote the runaway best-seller "J2EE without EJB" where they proved that you can build viable enterprise applications using J2EE without EJB.
Rod Johson's prototype framework turned into Spring and, as they say, the rest is history.

Juergen Hoeller was and is one of the key developers of the framework and has been the most active Spring developer since the open source project began from Rod Johnson's framework.

Simplicity and Evolution

Simplicity is a keyword for Juergen Hoeller.
"All that Spring is about is focusing on simple objects. This simple principle is sometimes called POJO, Plain Old Java Objects. All that Spring ever did, is doing and will be doing centres on simple objects such as Domain objects, service objects and event objects as the basis for your application," he said in a recent talk about the evolution of the Spring framework.
Another keyword for Spring is just that; evolution.
"Spring's strategy is avoid revolution. Avoid restarting from scratch. It is a careful evolution with old and new living side by side. Fitting radical new features in existing framework architecture is an ongoing challenge, but, surprisingly, it has worked so far," says Juergen Hoeller.
And he is right. The codebase for Spring is 7 years old and is spanning 4 generations of Java EE.

Attention to detail is very important for Juergen Hoeller.
"Small details may turn into major headaches, One wrong decision may prevent an entire path of evolution" he argues, which is why a project like Spring must be consistent in its design and naming choices.

Does Juergen Hoeller have a life?

Back in 2006 he told InfoQ that he did not have a normal life:
"In my day life I'm both Principal Consultant and CTO at Interface21 and also responsible as a technical lead for the Spring framework project which means there's a lot of coding which tends to shift into the night, the weekends and all the other time when normal people go out there and do something with their lives."
So, does Juergen Hoeller still not have a life?
"Since I switched to a principal engineer role and have been able to focus on development for a few years already, it’s all quite different. And we have a baby now which impacts on things as well," he tells the JAOO crew.
He still serves as the Spring Framework project lead, so he is still carrying quite a bit of responsibility which doesn’t stop at 5pm.
"My working times have to be flexible, but since I’m working from a home office, that’s not a problem at all," tells Juergen Hoeller.
At JAOO Juergen Hoeller will be talking about the upcoming Spring 3.1 release, which is scheduled for general availability in December 2010.

Passion: Breaking with established principles where necessary, while at the same time building bridges where possible

Juergen Hoeller on the Evolution of Spring: http://www.springsource.org/node/2720