How Many Java developers are There in the World?

Oracle says it’s 9,000,000. Wikipedia claims it’s 10,000,000. And the guys from NumberOf.net seem to be the most precise - they know that there are exactly 9,007,346 Java developers out there.

Nice numbers. I have used those articles as reference points while speaking about the potential market size for our memory leak detection tool. But something in these numbers has bothered me for years - there is no trustworthy and public analysis behind those numbers. Its just conjured up from thin air. So I finally thought I would do something about it and try to figure it out for good.
It proved out to be a challenging task. After all - with more than seven billion people on our planet I couldn't call everyone and ask them. Well, maybe I could, but if every call would take on average 20 seconds I would need at least 4,439 years to complete the survey. If I would not sleep nor eat nor rest. So I had to use other ways for estimation.

Good Developer, Bad Developer

Good Developer, Bad Developer

Good developer is an artist, a craftsman who enjoys the process of creation. Bad developer considers himself as a programmer, responsible for generating lines of code.

Good developer understands the problems of the customers. Bad developer understands only the technical problem at hand. Good developer does not define the why, but constantly strives to understand why. He’s responsible for the how, and still sees the big picture. Bad developer is focused on building classes and methods and configuration files, but does not get the big picture.

Good developer understands the complete architecture of the product. Bad developer knows only the components he’s written. Good developer fully understands the technologies that are used within the product. He understands what they are used for, and how they work internally.

Good developer is not afraid of new technologies but embraces them by quickly getting a grip. Bad developer only sticks to what he knows. His immediate reaction to any technical change is negative.

Good developer is constantly learning and improving his skills. Good developer reads technical articles, and finishes several technical books a year. Bad developer does not have time to learn. He’s always too busy with other stuff.