The only "systems language" is one that an OS with its accompanying device drivers are written in. Would you consider C a systems language? well, C is useless

The only "systems language" is one that an OS with its accompanying device drivers are written in. Would you consider C a systems language? well, C is useless under a LispOS, for example. Ditto for Java. If you wrote the whole OS in Java, presto, Java would be the language to write device drivers. IOW, "systems" is a relative term.