Interfaces are abused very often these days, especially in Java, when they are used to compose classes what in many cases breaks single responsibilty rule and leads to redundant code.
Updates (most recent on top):
UPDATE: I’ve corrected some spelling and language specific problems. Now, this tutorial should be easier to read and understand (at least that’s what I hope for).
UPDATE 2: Currently THREE.js exports multiple actions using blender exporter, so this tutorial in not suitable for exporters for THREE.js versions r62 and higher. It should work well with versions r56 up to r61
UPDATE: Originally this tutorial was written for THREE.js r56 and Blender 2.65 but lately I’ve tested it with THREE.js r60 and Blender 2.68a and it worked (actually it also worked with THREE.js versin “r61dev.”. whatever it means), so I believe that it works for the versions in between also.
Today I’ve solved a rather puzzling problem: creating model in Blender, animating it with armature and exporting the animation for THREE.js (r56) JSON format.