On Learning

I've been reading Pragmatic Thinking and Learning by Andy Hunt (who co-wrote the The Pragmatic Programmer) lately. The book brings up idea of second-order incompetence, which means that a novice at a particular skill is so unskilled that they don't even realize how unskilled they really are. This leads beginners to greatly overestimate their own ability. In many cases, it can lead a beginner to be more confident in their own skill than an expert.

The second-order incompetence theory applies to any skill in general, but I've noticed that it applies extremely well to programmers and their particular set of skills.


I've heard some programmers say that it takes anywhere from three days to three months to learn a new programming language. I personally feel that this is an extremely low estimate (I've been learning C++ for several years). Three days is barely enough time to learn the syntax of a new language. Three months is likely enough time to learn the syntax and a few common libraries of a language, but it isn't really enough time to get you beyond the "Advanced Beginner" skill level. It's probably just enough time to give you the confidence you need to be extremely dangerous.

The book goes on to explain that it really takes more on the order of ten years to truly master any non-trivial skill, whether it be playing chess, playing music, or flying an airplane. Peter Norvig quotes some of the same research when he advocates the ten year time scale for programmers in his article Teach Yourself Programming in Ten Years.

These ideas are hardly new. Socrates was onto a similar idea almost 2500 years ago when he said

"True knowledge exists in knowing that you know nothing."

In programming, as in almost any worthwile pursuit, this means that you have to give yourself time to reach a skill level high enough that you know how much you don't know. If you catch yourself feeling confident in a given language after only three days (or even three months), try to realize that you've probably only seen a tiny fraction of the what there is to see. Remember that 90% of an iceberg is below the surface.

Is blogspam ever okay?

Sometimes.

See this question for details.

NetBeans PMD plugin

I was installing NetBeans on a new computer recently (and prompted by a question on StackOverflow), so it came to my attention that, due to the blazing fast speed of NetBeans development, the instructions for installing the NetBeans PMD plugin are a little outdated. Here's an updated set of instructions*.

1. Download the latest PMD release from SourceForge.
2. Unzip the zip file to any directory. I put mine in C:\Program Files\Java\pmd-netbeans60-2.2.1, right next to my JDK directory. You'll see that the zip file contained a .nbm file that encapsulates the plugin.
3. Run NetBeans and click Tools -> Plugins
4. Go to the Downloaded tab on the Plugins dialog.
5. Click on the Add Plugins... button at the top of the tab.
6. Navigate to the directory where you unzipped the PMD plugin zip file.
7. Select the file named pmd.nbm.
8. Click the Open button.

You'll get a dialog saying that the plugin isn't signed, asking you whether you want to accept it anyway or cancel the installation. You'll need to accept it without a signature in order to use the plugin. You'll need to restart NetBeans after installation is complete.

You can run PMD by selecting a single source code file or an entire source package, then selecting Tools -> Run PMD (or Ctrl-Alt-P) from the main NetBeans menu.

To change from the default rule set go to Tools -> Options on the main NetBeans menu. On the Options dialog, select the Miscellaneous toolbar button, then the PMD tab. On the PMD tab you can press the Manage Rules... button to change the default ruleset, or press the Manage Rulesets... button to create a custom ruleset of your own.

*Note: I'm doing the installation for NetBeans 6.1 running on Windows XP as I write these instructions. I've verified these instructions using NetBeans 6.0.1 on Ubuntu.