Programming is rarely ever complete. Change is a constant in an enterprise software systems, and making a program difficult to or expensive to change is an opportunity to cost to your business money. Poor code quality in your software will jeopardize your company’s future, make agile changes impossible, and make maintenance a nightmare.
In this article by Roedy Green helps us understand how easy it is to make a program difficult to manage and impossible to update without significant risk.
In the interests of creating employment opportunities in the Java programming field, I am passing on these tips from the masters on how to write code that is so difficult to maintain, that the people who come after you will take years to make even the simplest changes. Further, if you follow all these rules religiously, you will even guarantee yourself a lifetime of employment, since no one but you has a hope in hell of maintaining the code. Then again, if you followed all these rules religiously, even you wouldn’t be able to maintain the code!
You don’t want to overdo this. Your code should not look hopelessly unmaintainable, just be that way. Otherwise it stands the risk of being rewritten or refactored.
To foil the maintenance programmer, you have to understand how he thinks. He has your giant program. He has no time to read it all, much less understand it. He wants to rapidly find the place to make his change, make it and get out and have no unexpected side effects from the change.
He views your code through a toilet paper tube. He can only see a tiny piece of your program at a time. You want to make sure he can never get at the big picture from doing that. You want to make it as hard as possible for him to find the code he is looking for. But even more important, you want to make it as awkward as possible for him to safely ignore anything.
Programmers are lulled into complacency by conventions. By every once in a while, by subtly violating convention, you force him to read every line of your code with a magnifying glass.
You might get the idea that every language feature makes code unmaintainable — not so, only if properly misused.