Today, Mike sends us a Java Representative Line that is, well, very representative. The line itself isn't inherently a WTF, but it points to WTFs behind it. It's an omen of WTFs, a harbinger.
ArrayList[] data = new ArrayList[dataList.size()];
dataList is an array list. This line creates an array of arraylists, equal in length to dataList. Why? It's hard to say for certain, but the whiff I get off it is that this is an attempt to do "object orientation by array(list)s." Each entry in dataList is some sort of object. They're going to convert each object in dataList into an arraylist of values. This also either is old enough to predate Java generics (which is its own WTF), or explicitly wants a non-generic version so that it can do this munging of values into an array.
Mike provided no further explanation, so that's all speculation. But what is true is that when I see a line like that, my programmer sense starting tingling- something is wrong, even if I don't quite know what.