Why Have an Abstract Interface?

Posted by ryan
at 2:06 PM on Monday, February 14, 2005



I have run across the following in both some JBoss source that I’ve seen as well as the “new Interface” wizard in Eclipse… What is the purpose of having an interface and its methods defined as being abstract? To me, this is completely redundant:

abstract interface MyIfc {
   public abstract whatsThePoint();
}

If it’s an interface, of course you have to implement its definition – which is what being abstract means. What is the point of basically specifying the same thing twice? I know I’m missing something here?

Define the Spring Framework w/o using "IOC" or "Dependency Injection" 5

Posted by ryan
at 12:45 PM on Thursday, February 03, 2005



I am often asked (i.e. once every other year) by my coworkers, “What is Spring”? I usually launch into a long-winded diatribe of what it is followed by how it’s used and what it allows you to do. Most people get it, but I have decided it’s time to solidify that base definition of Spring so that it can be taken, alone, as a concise yet accurate definition of Spring. The people who ask me this are often bright Java guys, just unaware of the base concepts of Spring, IOC etc… so the definition can’t contain any of those buzzwords typically associated with Spring (kind of like explaining what “the” means without using the word “the”). My first attempt looked something like this:

Spring is a framework for transparently forming relationships between objects.

Ok, that statement is accurate but hardly embodies the full power of the framework. The word “transparent” is key and should be kept. We should also convey it’s lightweight nature and maybe the fact that it allows for the interception of it’s wired components using aspects? (but let’s not use the word “aspect”):

Spring is a lightweight framework that allows for the transparent management, wiring and interception of application components.

Ok, that’s a pretty tight definition of the base Spring functionality. Remember, I’m not trying to tell somebody everything Spring can do in one sentence, I’m just trying to convey the major functionality and potential of the framework. I’d like to add something in there about Spring’s ability to both replace or work with J2EE technology as Spring’s documentation goes to great length to stress both:

Spring is a lightweight framework, working in concert with or replacing J2EE, that allows for the transparent management, wiring and interception of application components.

But it also works in concert with many other standard Java frameworks and specs such as Hibernate, JDBC etc…, not just “J2EE”:

Spring is a lightweight framework that allows for the complete abstraction and encapsulation of implementation-specific technologies, like EJB, JDBC, Hibernate and others, by providing the ability to transparently manage, wire and intercept application components.

I feel like that’s a pretty good stab at it. My only fear is that I’m so engrossed in the making of the definition that it makes perfect sense to me while making absolutely no sense to any other reasonable person. That’s where you come in.. thoughts?