When implementing controller support in games, the default value for all axis starts at -1, which is incorrect. They should be initialized to 0.
One a button from each axis is pressed, the controllers work as intended.
For example, lets say I have a controller with a simple d-pad. The default value for axis 0 is -1 (up) and for axis 1 is -1 (left). If I coded my d-pad to control a character in my game, my character would start out walking up and to the left.
This is a minor issue but takes a lot of code to fix and some user input (such as forcing a user to pressed a button from each axis to set them back to zero after they release the button).
This was reported before on the forums several years ago, but since it is a JInput bug and not a Slick2D bug, nothing has changed.