Java streams have findAny and findFirst methods out of the box. And they works fine, they do exactly what they say: it gets one of the matches. But in my experience, often I don't want 'one of the matches', I want there to be a single match, and I want that one. The problem For example, finding the instances in a stream of customers var formExpressionInstance = getCustomers().stream() .filter(instance -> isDateInRange(ferenceDate, instance.getDateStart(), instance.getDateEnd())) .findFirst() If there are multiple matches, maybe... full post»

If you are using overloads In Java, and one of them uses varargs, then there's a rare pitfall to be aware of. I ran into this a while back. There were two methods, similar to this: public void method( @Nullable Object first, @Nullable String second, @Nullable Integer third, @Nullable BigDecimal fourth, @Nullable Double fifth ) throws Exception { and public void method( @Nonnull Integer... varargs ) throws Exception { Then, someone added a sixth argument to the first method. Simultaneously... full post»

It is no secret that Javascript isn't the most well-designed language, and these points have probably been made a billion times, but now it's my turn! Note that this isn't a criticism about a lack of expressiveness. You can create great things with javascript. But you can also footgun yourself very easily, which is what I'm criticizing there. Most languages are expressive, but good ones help you avoid mistakes instead of making them. You can pass more or fewer arguments... full post»

Recently, I've been interested in designing software to make hard-to-find bugs reveal themselves at compile-time. An idea I've read about (I forgot where) that I found fascinating is the use of a special type for IDs in objects that represent database rows. Problem For example, there may be a User table and a Posts table in the database, with each post belonging to one user. Each of these would be mapped to a class/struct in the programming language. Perhaps each... full post»