code: public void applyJournalEntryCommand(Commit<JournalEntryCommand> commit) {
        JournalEntry entry;
        try {
          entry = JournalEntry.parseFrom(commit.command().getSerializedJournalEntry());
        } catch (Throwable t) {
          ProcessUtils.fatalError(LOG, t, "Encountered invalid journal entry in commit: {}.", commit);
          throw new IllegalStateException();
        }
        applyEntry(entry);
      }
docs: Applies a journal entry commit to the state machine.
  
  This method is automatically discovered by the Copycat framework.
  
  @param commit the commit