Program: 57981
Project: 57981
Buggy source:
@Override public int handle(CommandCaller caller,String input){
  String[] parts=input.split("String_Node_Str");
  String[] args;
  String command=parts[0].toLowerCase();
  if (parts.length == 1) {
    args=new String[0];
  }
 else {
    args=new String[parts.length - 1];
    System.arraycopy(parts,1,args,0,args.length);
  }
  Command cmd=null;
  for (  Command c1 : this.commands) {
    if (c1.getCommand().equalsIgnoreCase(command) || c1.getAliases().contains(command)) {
      cmd=c1;
      break;
    }
  }
  if (cmd == null) {
    caller.message(C.NOT_VALID_SUBCOMMAND);
{
      final String[] commands=new String[this.commands.size()];
      for (int i=0; i < commands.length; i++) {
        commands[i]=this.commands.get(i).getCommand();
      }
      final String bestMatch=new StringComparison<String>(args[0],commands).getBestMatch();
      caller.message(C.DID_YOU_MEAN,"String_Node_Str" + bestMatch);
    }
    return CommandHandlingOutput.NOT_FOUND;
  }
  if (!cmd.getRequiredType().isInstance(caller.getSuperCaller())) {
    if (caller instanceof PlotPlayerCaller) {
      caller.message(C.NOT_CONSOLE);
    }
 else {
      caller.message(C.IS_CONSOLE);
      return CommandHandlingOutput.CALLER_OF_WRONG_TYPE;
    }
  }
  if (!caller.hasPermission(cmd.getPermission())) {
    caller.message(C.NO_PERMISSION,cmd.getPermission());
    return CommandHandlingOutput.NOT_PERMITTED;
  }
  Argument[] requiredArguments=cmd.getRequiredArguments();
  if (requiredArguments != null && requiredArguments.length > 0) {
    boolean success=true;
    if (args.length < requiredArguments.length) {
      success=false;
    }
 else {
      for (int i=0; i < requiredArguments.length; i++) {
        if (requiredArguments[i].parse(args[i]) == null) {
          success=false;
          break;
        }
      }
    }
    if (!success) {
      caller.sendRequiredArgumentsList(this,cmd,requiredArguments);
      return CommandHandlingOutput.WRONG_USAGE;
    }
  }
  try {
    boolean a=cmd.onCommand(caller,args);
    if (!a) {
      String usage=cmd.getUsage();
      if (usage != null && !usage.isEmpty()) {
        caller.message(usage);
      }
      return CommandHandlingOutput.WRONG_USAGE;
    }
  }
 catch (  final Throwable t) {
    t.printStackTrace();
    return CommandHandlingOutput.ERROR;
  }
  return CommandHandlingOutput.SUCCESS;
}

Fixed version (ground truth):
@Override public int handle(CommandCaller caller,String input){
  String[] parts=input.split("String_Node_Str");
  String[] args;
  String command=parts[0].toLowerCase();
  if (parts.length == 1) {
    args=new String[0];
  }
 else {
    args=new String[parts.length - 1];
    System.arraycopy(parts,1,args,0,args.length);
  }
  Command cmd=null;
  cmd=this.commands.get(command);
  if (cmd == null) {
    caller.message(C.NOT_VALID_SUBCOMMAND);
{
      final String[] commands=new String[this.commands.size()];
      for (int i=0; i < commands.length; i++) {
        commands[i]=this.commands.get(i).getCommand();
      }
      final String bestMatch=new StringComparison<String>(args[0],commands).getBestMatch();
      caller.message(C.DID_YOU_MEAN,"String_Node_Str" + bestMatch);
    }
    return CommandHandlingOutput.NOT_FOUND;
  }
  if (!cmd.getRequiredType().isInstance(caller.getSuperCaller())) {
    if (caller instanceof PlotPlayerCaller) {
      caller.message(C.NOT_CONSOLE);
    }
 else {
      caller.message(C.IS_CONSOLE);
      return CommandHandlingOutput.CALLER_OF_WRONG_TYPE;
    }
  }
  if (!caller.hasPermission(cmd.getPermission())) {
    caller.message(C.NO_PERMISSION,cmd.getPermission());
    return CommandHandlingOutput.NOT_PERMITTED;
  }
  Argument[] requiredArguments=cmd.getRequiredArguments();
  if (requiredArguments != null && requiredArguments.length > 0) {
    boolean success=true;
    if (args.length < requiredArguments.length) {
      success=false;
    }
 else {
      for (int i=0; i < requiredArguments.length; i++) {
        if (requiredArguments[i].parse(args[i]) == null) {
          success=false;
          break;
        }
      }
    }
    if (!success) {
      caller.sendRequiredArgumentsList(this,cmd,requiredArguments);
      return CommandHandlingOutput.WRONG_USAGE;
    }
  }
  try {
    boolean a=cmd.onCommand(caller,args);
    if (!a) {
      String usage=cmd.getUsage();
      if (usage != null && !usage.isEmpty()) {
        caller.message(usage);
      }
      return CommandHandlingOutput.WRONG_USAGE;
    }
  }
 catch (  final Throwable t) {
    t.printStackTrace();
    return CommandHandlingOutput.ERROR;
  }
  return CommandHandlingOutput.SUCCESS;
}