1187         }
1188         return true;
1189     }
1190 
1191     private boolean cmdExit() {
1192         regenerateOnDeath = false;
1193         live = false;
1194         if (!replayableHistory.isEmpty()) {
1195             // Prevent history overflow by calculating what will fit, starting
1196             // with must recent
1197             int sepLen = RECORD_SEPARATOR.length();
1198             int length = 0;
1199             int first = replayableHistory.size();
1200             while(length < Preferences.MAX_VALUE_LENGTH && --first >= 0) {
1201                 length += replayableHistory.get(first).length() + sepLen;
1202             }
1203             String hist = replayableHistory
1204                     .subList(first + 1, replayableHistory.size())
1205                     .stream()
1206                     .reduce( (a, b) -> a + RECORD_SEPARATOR + b)
1207                     .get();
1208             prefs.put(REPLAY_RESTORE_KEY, hist);
1209         }
1210         fluffmsg("jshell.msg.goodbye");
1211         return true;
1212     }
1213 
1214     boolean cmdHelp(String arg) {
1215         ArgTokenizer at = new ArgTokenizer(arg);
1216         String subject = at.next();
1217         if (subject != null) {
1218             Command[] matches = commands.values().stream()
1219                     .filter(c -> c.command.startsWith(subject))
1220                     .toArray(size -> new Command[size]);
1221             at.mark();
1222             String sub = at.next();
1223             if (sub != null && matches.length == 1 && matches[0].command.equals("/set")) {
1224                 at.rewind();
1225                 return printSetHelp(at);
1226             }
1227             if (matches.length > 0) {

1187         }
1188         return true;
1189     }
1190 
1191     private boolean cmdExit() {
1192         regenerateOnDeath = false;
1193         live = false;
1194         if (!replayableHistory.isEmpty()) {
1195             // Prevent history overflow by calculating what will fit, starting
1196             // with must recent
1197             int sepLen = RECORD_SEPARATOR.length();
1198             int length = 0;
1199             int first = replayableHistory.size();
1200             while(length < Preferences.MAX_VALUE_LENGTH && --first >= 0) {
1201                 length += replayableHistory.get(first).length() + sepLen;
1202             }
1203             String hist = replayableHistory
1204                     .subList(first + 1, replayableHistory.size())
1205                     .stream()
1206                     .reduce( (a, b) -> a + RECORD_SEPARATOR + b)
1207                     .getWhenPresent();
1208             prefs.put(REPLAY_RESTORE_KEY, hist);
1209         }
1210         fluffmsg("jshell.msg.goodbye");
1211         return true;
1212     }
1213 
1214     boolean cmdHelp(String arg) {
1215         ArgTokenizer at = new ArgTokenizer(arg);
1216         String subject = at.next();
1217         if (subject != null) {
1218             Command[] matches = commands.values().stream()
1219                     .filter(c -> c.command.startsWith(subject))
1220                     .toArray(size -> new Command[size]);
1221             at.mark();
1222             String sub = at.next();
1223             if (sub != null && matches.length == 1 && matches[0].command.equals("/set")) {
1224                 at.rewind();
1225                 return printSetHelp(at);
1226             }
1227             if (matches.length > 0) {