Current FXMLLoader documentation should be corrected:
getController():
"Sets the controller associated with the root object. The value passed to this method is used as the value of the fx:controller attribute. This method must be called prior to loading the document when using controller event handlers when an fx:controller attribute is not specified in the document."

These words belong to setController(java.lang.Object controller) not to this one. getController's doc was mistakenly updated instead of setController's.

setRoot()'s docs contain wrong escape characters "%gt;". Should be ">".