Database administrators have the possibility to set lifetimes for user passwords. This can be considered a security feature, so that passwords get updated regularly. But if one of your software services logs into the database with such an account, you want to know when the password expires in good time before this happens, so that you can update the password. Otherwise your service will stop working unexpectedly.
Of course, you can mark the date in your calendar in order to be reminded beforehand, and you probably should. But there is an additional measure you can take. The database administrator can not only set the lifetime of a password, but also a “grace period”. For example:
ALTER PROFILE app_user LIMIT PASSWORD_LIFE_TIME 180 PASSWORD_GRACE_TIME 14;
This SQL command sets the password life time to 180 days (roughly six months) and the grace period to 14 days (two weeks). If you log into the database with this user you will see a warning two weeks before the password will expire. For Oracle databases the warning looks like this:
ORA-28002: the password will expire within 14 days
But your service logs in automatically, without any user interaction. Is it possible to programmatically detect a warning like this? Yes, it is. For example, with JDBC the following code detects warnings after a connection was established:
// Error codes for ORA-nnnnn warnings
static final int passwordWillExpireSoon = 28002;
static final int accountWillExpireSoon = 28011;
void handleWarnings(Connection connection) throws SQLException {
SQLWarning warning = connection.getWarnings();
while (null != warning) {
String message = warning.getMessage();
log.warn(message);
int code = warning.getErrorCode();
if (code == passwordWillExpireSoon) {
System.out.println("ORA-28002 warning detected");
// handle appropriately
}
if (code == accountWillExpireSoon) {
System.out.println("ORA-28011 warning detected");
// handle appropriately
}
warning = warning.getNextWarning();
}
}
Instead of just logging the warnings, you can use this code to send an email to your address, so that you will get notified about a soon-to-be-expired password in advance. The error code depends on your database system.
With this in place you should not be unpleasantly surprised by an expired password. Of course, this only works if the administrator sets a grace period, so you should agree on this approach with your administrator.
If we were to choose the holy book of software development, we probably couldn’t agree on one or even a dozen titles. And that is a good thing, because there is no one true way of software development. Clean Code by Robert C. Martin would maybe show up in the late contenders. But if we were to choose the most preachy book of software development, well, I have a favorite. This book is so loud that you cannot ignore it. And it is so opinionated that you’re either nodding your head like a heavy metal fan or writhing in averseness. That’s a good thing, too. Because it forces you to think. Your immediate emotional answer needs support by rational arguments and this book will provide you with ample opportunity to gather arguments for your consent or rejection. What this book probably won’t do is leave you unaffected. When it came out in 2008, it was an instant classic. You could spice up any gathering of software developers by making a statement about this book, be it pro or contra. And even today, ten years later, I would say that even if the loudness is deafening, the clarity of the messages makes this book a worthwhile read for every software developer. My grief with it is foremost that for a book called “Clean Code”, some examples of actual code are quite dirty or even plain wrong. Read it with an active mind and it will be a cornerstone of your professional career. But be careful, it seems that currently printed instances have physical quality problems.
Ever since Extreme Programming hit the (european) scene in 1999, I was curious about Test Driven Development (TDD). I tried automated testing and unit tests whenever I could, read books and later watched videos about the topic. But I never grokked it. It just didn’t work for me and I didn’t even know why. My most feared trap was the one-two-everything syndrome, where you write two simple tests and then have to implement the whole algorithm to fulfill the third test. It was always the third test that broke my rhythm. I tried to exchange experience with TDD practitioners, but their own examples were mostly trivial and my examples always led nowhere (for reference: Try a simple Game of Life in TDD style). I felt dumb and inadequate. When Robert C. Martin (the author of Clean Code) told the developer world that you are either “TDD or not professional” (read 
Some years after the GOOS experience, another summer beach holiday was due and as usual, I included a software development book in my luggage. “Domain Driven Design” by Eric Evans came out in 2003 and was praised by some and ignored by most, including me. It took me ten years to finally read it and when I did, it hit me hard. Since my early days as a programmer, I tried to build a meaningful data model with actual types for each program I developed. But it occurred to me that I did it half-heartedly all the time. It shouldn’t stop at a data model, it should be a complete domain model. And for that to work, you need to grok the domain. I review a lot of my code before that insight and always find it funny how I invested effort in my models but more often than not stayed in the technical realm. I cannot say that my programming has changed much from the book, as most concepts meandered through the community since 2003 and were picked up by me mostly under different names. But my software development approach has changed dramatically. I don’t start my thinking from the technical side anymore. And that helps with “business alignment” and all the other magic words that finally have real tangible benefit. And I can now pinpoint when that alignment loosens and employ counter-measures instead of ending up in a special case hell. The best thing was that this book doesn’t require a laptop so I got to sit on the beach that summer with the book in my hands and my head in the clouds. It might be old, but it’s still gold.
I anxiously waited for this book to be printed. Not because I pre-ordered, but because I held talks, workshops and lectures about the topic before the book was available. And I wanted to make sure that I’m not telling nonsense. But Robert C. Martin took his time and delayed the deadline month after month. Then, nearly a year later, the book reached the stores in late 2017. So I would have to wait for my winter holiday to read it. I couldn’t wait and began right away. The book is a slow burner and feels like a long introduction. By the time the central proposition is revealed (and yes, it reads like good unagitated spy thriller at times), you’ve probably already figured it out yourself. And that’s a good thing in my mind, because it feels as if it was your idea and Uncle Bob is just there to nod and congratulate you for your intellect. This book is so many times less preachy than “Clean Code”. If we compare spy thriller literature, this is a John le Carré while Clean Code would be an Ian Fleming (James Bond). “Clean Architecture” is not about programming, it talks about software architecture, a topic that I missed greatly in my early developer years. I liked this book so much 
All the other books talk about different aspects of programming, software development or related technical topics. But what about a book that raises a simple question: “Why is IT technology so complicated?”. And gives the answer: “Because we want it this way.”. That’s actually true. In a world without most of the restrictions of the physical world, we were unable to build solutions that actually helped us and came up with machines and software that overwhelmed most people. It needed a whole new generation of “digital natives” until concepts like internal operation modes (e.g. insert vs. overwrite) were intuitively understood. Not because they became simpler, we were just used to the complexity. Alan Cooper described the problem and gave at least hints for solutions in 1999, nearly 20 years ago. That’s the timespan of a generation. This book made me think hard about the status quo I silently had accepted with technology. It just was like it was, what else could there be? If I reveal a tiny bit of different approaches I can think of now, I’m often confronted with incomprehension. Not because I’m particularly clever and everyone else is dumb, but because there seems to be no problem if you’ve grown accustomed to it. If you want to see some of the pain other (older) people feel when interacting with technology and software, read this book. It is an eye-opener to common problems no software developer ever had. It is the first step into the world of UX (user experience), where it’s not as important if the developer feels alright but if the user feels at least adequate. It might be a classic and feel a bit outdated and weak on the solution side, but to understand the problem properly is the first step to appreciate possible answers. And Alan Cooper didn’t stop there. Read his 
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Martin Fowler was a very productive author in the late nineties. I’ve read most of his books from this period, if maybe with a few years delay. “
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