I just tried to preview a .class file from projectx in F26 konqueror
with this result. Attempts to use other tools also fail, and el7 has a
similar problem. Google finds related complaints from Windows 10.
Apparently the class I hoped to examine isn't there - but that's another
story.
Failed to extract plugin meta data from
'/usr/lib64/qt5/plugins/kf5/parts/kjavaappletviewer.so'
John P