I made the assumption that we would still have access to the original source code. So it wouldn't be so hard to translate Java to another modern language, e.g.

I made the assumption that we would still have access to the original source code. So it wouldn't be so hard to translate Java to another modern language, e.g. one of the most modern being Go. On the other hand, so few people know COBOL these days that even with source code, translating those systems would take considerably longer.