JT open CAD format (.jt) is unfortunately not well supported in traditional CAD programs, which means that the only way how to convert it to something (like SolidWorks) else would be to find a dedicated CAD converter like the CrossManager, or perhaps find some plugin that adds support for JT format.
Open JT file Open SLDASM fileA CAD converter with huge format support
A CAD visualizaton, analyzation and translating system