I don't think we need to prescribe one true form for this particular case.  Sometimes more than one style is okay.  

Personally, I don't like the idea of moving the actual numeric values off to the top of the class, because each value is now used exactly once.  To replace them with class constants only introduces an extra level of indirection, which makes it harder to see if all the clam exit codes have been handled appropriately.

Again, syntax highlighting helps a lot.  I think the switch statement is quite readable (and "visually parseable") here: https://github.com/zanata/zanata-server/blob/c456de543efcaf8d60262d8046a6bda9b146bed3/zanata-war/src/main/java/org/zanata/rest/service/VirusScanner.java#L125

@carlosmunoz What do you think?