This is one of the more interesting recent Stack Overflow questions: Why does Iterable not provide stream() and parallelStream() methods? At first, it might seem intuitive to make it straight-forward to convert an Iterable into a Stream, because the two are really more or less the same thing for 90% of all use-cases. Granted, the … Continue reading Really Too Bad that Java 8 Doesn’t Have Iterable.stream()
The Inconvenient Truth About Dynamic vs. Static Typing
Sometimes there are these moments of truth. They happen completely unexpectedly, such as when I read this tweet: https://twitter.com/whileydave/status/536422407297171457 David is the author of the lesser-known but not at all lesser-interesting Whiley programming language, a language that has a lot of static type checking built in it. One of the most interesting features of the … Continue reading The Inconvenient Truth About Dynamic vs. Static Typing
Don’t be “Clever”: The Double Curly Braces Anti Pattern
From time to time, I find someone using the double curly braces anti pattern (also called double brace initialisation) in the wild. This time on Stack Overflow: Map source = new HashMap(){{ put("firstName", "John"); put("lastName", "Smith"); put("organizations", new HashMap(){{ put("0", new HashMap(){{ put("id", "1234"); }}); put("abc", new HashMap(){{ put("id", "5678"); }}); }}); }}; In case … Continue reading Don’t be “Clever”: The Double Curly Braces Anti Pattern
Do You Really Understand SQL’s GROUP BY and HAVING clauses?
There are some things in SQL that we simply take for granted without thinking about them properly. One of these things are the GROUP BY and the less popular HAVING clauses. Let's look at a simple example. For this example, we'll reiterate the example database we've seen in this previous article about the awesome LEAD(), … Continue reading Do You Really Understand SQL’s GROUP BY and HAVING clauses?
How to Integrate Commercial Third-Party Artefacts into Your Maven Build
According to a recent survey by ZeroTurnaround's RebelLabs, Maven is still the leading Java build platform. The current market share distribution, according to RebelLabs is: Maven with 64% Ant + Ivy with 16.5% Gradle with 11% Yet, at the same time, Maven is often criticised for being a bit obscure and intrusive. Compared to runner-ups … Continue reading How to Integrate Commercial Third-Party Artefacts into Your Maven Build
Use MySQL’s Strict Mode on all new Projects!
MySQL is a database that has been bending the SQL standard in ways that make it hard to move off MySQL. What may appear to be a clever technique for vendor lockin (or maybe just oversight of the standard) can be quite annoying in understanding the real meaning of the SQL language. One such example … Continue reading Use MySQL’s Strict Mode on all new Projects!
jOOQ Tip of the Day: Discover all Primary Keys
We've recently encountered this interesting use-case on the jOOQ user group. How do you discover all primary keys of your schema via the jOOQ API? There are two ways: Using the generated meta data Using runtime meta data Let's see how it works: Using the generated meta data This is straightforward. If you're using Java … Continue reading jOOQ Tip of the Day: Discover all Primary Keys
Don’t Migrate to MariaDB just yet. MySQL is Back!
Now that I have your attention, I'd like to invite you to a critical review of where we're at in the MySQL vs. MariaDB debate. Around one month ago, I visited Oracle Open World 2014, and I've met with Morgan Tocker, the MySQL community manager at Oracle to learn about where MySQL is heading. Who … Continue reading Don’t Migrate to MariaDB just yet. MySQL is Back!
Have You Ever Wondered About the Difference Between NOT NULL and DEFAULT?
When writing DDL in SQL, you can specify a couple of constraints on columns, like NOT NULL or DEFAULT constraints. Some people might wonder, if the two constraints are actually redundant, i.e. is it still necessary to specify a NOT NULL constraint, if there is already a DEFAULT clause? The answer is: Yes! Yes, you … Continue reading Have You Ever Wondered About the Difference Between NOT NULL and DEFAULT?
Don’t Miss out on Awesome SQL Power with FIRST_VALUE(), LAST_VALUE(), LEAD(), and LAG()
If you're using a commercial database or PostgreSQL / Firebird / CUBRID, you will be able to take advantage of the full power of window functions. We've blogged about window functions' awesomeness a couple of times, in particular about ROW_NUMBER(), RANK(), DENSE_RANK(). Today, we're going to look into some awesome window functions that produce values … Continue reading Don’t Miss out on Awesome SQL Power with FIRST_VALUE(), LAST_VALUE(), LEAD(), and LAG()