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    <p>I wrote a blog post on that topic a while ago: <a href="http://codebetter.com/patricksmacchia/2009/02/01/understanding-code-static-vs-dynamic-dependencies/" rel="nofollow">Understanding Code: Static vs Dynamic Dependencies</a>. Basically you need to make a difference between <i>static dependencies</i>, those that are resolved by the compiler at compile-time, and <i>dynamic dependencies</i>, those that are resolved by the runtime (JVM or CLR) at run-time.</p> <p><i>static dependencies</i> are typically provoked by calls to static/final methods, read/write to a field, in the definition of the class C the implementation of the interface I by C ... all these associations between code elements that can be found explicitly in the bytecode and source code.</p> <p><i>dynamic dependencies</i> are typically provoked by everything that abstracts a method call at compile time, like calls to abstract/virtual methods (polymorphism), variables or parameters typed with an interface (the implementation class is abstracted at compile-time), but also <i>delegates</i> (.NET) or pointers to function (C++).</p> <p>Most of the time, when you'll read about dependencies in the literature, they are talking about <i>static dependencies</i>.</p> <p>A <i>static dependencies</i> is direct (meaning not transitive). A tool like <a href="http://www.NDepend.com" rel="nofollow">NDepend</a> that I mention in the blog post, can also infer <i>indirect (or call it transitive) static dependencies</i> from the set of <i>direct static dependencies</i>.</p> <p>The idea I defend in the blog post is that <b>when it comes to understand and maintain a program, one needs to focus mostly on the static dependencies, the ones found in the source code.</b>. Indeed, abstractions facilities are used to, well ... abstract, implementation for callers. This makes source code much more easy to develop and maintain. There are however situations, typically at debugging time, where one needs to know what's really behind an abstraction at run-time.</p>
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    1. POWhen exactly does a class/package depend on another?
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    1. USPatrick from NDepend team
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    1. COHow funny is that: I was just listening to your hanselminute-interview while you wrote this post. I particularly liked your comment that non-linear metrics are too indirect and hence too vague to be useful (did I grasp that correctly?). Do you know of any tool for Java where I can query metrics as in your NDepend (deltas included)? I find that awesome! And thanks a lot for your blog post, I'll definitely read it :)
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    2. COI read your blog post and it gave me some insights, thanks a lot :) I do have some questions left, though: the ones I posted as reply to LeleDumbo's post, and whether my examples where the static dependencies graph is not a sub-graph of the dynamic one, given at http://stackoverflow.com/questions/7070570/understanding-compile-vs-run-time-dependencies/7323704#7323704, are true.
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    3. COYep you grasped it correctly :) Glad this blog post was useful to you. For Java try XDepend.com, aka NDepend for Java.
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