Which framework JOSM uses for importing and rendering .osm files?

I’m making my own application and I want to add offline import and rendering of .osm files. I’m interested in which framework JOSM uses for importing and rendering .osm files? Thanks

Josm uses the java SAX parser to read XML data from an .osm file or from the server.
For rendering, Josm uses javax.swing and it’s own internal code.