I doubt if it is possible to do this with java, especially without third party libraries. Both DWG and OBJ are binary formats and there is no built in libraries to interpret these formats.
There is only 1 java open source library that I am aware of that can parse a AutoCAD dxf file(Kabeja) , but this will mean converting a dwg to a dxf file.
There could be commercial libraries available which probably can do this.
I doubt if it is possible to do this with java, especially without third party libraries. Both DWG and OBJ are binary formats and there is no built in libraries to interpret these formats.
There is only 1 java open source library that I am aware of that can parse a AutoCAD dxf file(Kabeja) , but this will mean converting a dwg to a dxf file.
There could be commercial libraries available which probably can do this.