Newbie needs help loading assets

Hi, I’m Peter a computer science student. Currently I’m working on a project for my studies! I’m building a plugin for Eclipse including a small simulator which should contain a 3D model of a Android Phone. Since a few days now I’m trying to export, convert and do some magic in order to get a 3D model which I’m able to load. I tried it already using Blender, Sketchup, Converted to Ogre Xml, to OBJ, to 3ds but nothing worked. The last thing I tried to do was to convert a OBJ file to a J3O file, first I got some Warnings Polygon or Edge…Ignored I was able to fix this but no model is display when trying to load it. Actually
I have no problems with java just with this crappy process of converting a model and loading it. Actually I’m quite fustrated and usually I’m not asking for help but in this case I have to admit that my knowledge about 3D things is to low. So please can somebody help me?

The model I’m trying to load is this one:

https://3dwarehouse.sketchup.com/warehouse/getpubliccontent?contentId=2d794966-be86-42b7-b2c2-502aea1bcd9e&fn=Nexus-5.skp

Can anybody give me some hints how to archive this?

Thank you in advance

Simple but important question, do you have a light in your scene?
Cause without there will be nothing visible.

Does it work with a simpler model? eg make a cube in blender and load that.