JME blender importer cant be adapted to import blender cycles material, the incompatibilities seems too much, right?
So I found these options below, they seem to basically allow the cycles material to be exported into simple textures that are compatible/usable by JME3.
I did it before as follow baking make the rendered result as image and then apply it as diffuse map image
But in my case the result was not fine, so I remake it using texture paint, it gives me better result in the game play, your case might be different
But about Texture Baking …
I think Even though it is cool but it’s use case is in more advanced places (like in modern AAA games) . For now I prefer to just stick to some simple techniques unless I am a pro !
But if you make any success about using it please let us know
sometimes baking used as well, for optimization for example lights if you have a none moving light it is recommended to do light baking in order to have the light effect pre-rendered and take the burden of the physics engine