90% of C should be pretty easy to translate, but of course, the devil (and a lot of functionality in existing libraries) is in the details.
There would be probably money in translating COBOL to Java, but maybe there are solutions already?
Native C libraries (libc, libmath, ...) are just directly used from Java, not translated.
Yes, there is a lot of money in Cobol/Fortran to Java. Many tried, none successful (I know many stories). We'll look into those two languages in the future. But creating real translators takes years.
There is, Proyect NACA (http://developers.slashdot.org/story/09/06/24/1915205/Automa...).
Have a look at the generated codeif you want a good laugh, it translated COBOL code to Java line by line.
(Because "just change" usually ends up creating other problems. Been there, done that, "code is wrong but works" and when you try to fix stuff breaks)