[jfengel]

The rapid change in Python is an indication that programming is different, rather than Java per se. Python, Java, and C all serve radically different programming niche.

The increase in Python tells you that its niche is increasing. It is, among other things, the language of data science and machine learning, which has a huge upswing lately. But that doesn't affect the absolute number of Java or C projects or jobs. It just tells you that a new thing is appearing.

If there is a chance in Java's utility, you see it more in C++ and C#, which occupy more similar niches. It's notable that C# is picking up; that's a trend that might be worth noting. And it's a bit puzzling that Java should fall below C++, and I suspect it has more to do with the vagaries of the metric.

But Java is for general-purpose programming, and that niche doesn't seem to be going away any time soon. If you want to get into data science, then by all means go learn Python. But that's less about picking up a new tool set as a change in careers.