Program: 183971
Project: 183971
Buggy source:
@Override public boolean onCommand(CommandSender slapper,Command command,String label,String[] split){
  if (plugin.usePermissions) {
    if (!(plugin.permissionHandler.has((Player)slapper,"String_Node_Str"))) {
      slapper.sendMessage(ChatColor.RED + "String_Node_Str");
      return true;
    }
  }
 else   if (!(slapper.isOp())) {
    slapper.sendMessage(ChatColor.RED + "String_Node_Str");
    return true;
  }
  String slapperName;
  if (slapper instanceof Player) {
    Player slapperCast=(Player)slapper;
    slapperName=slapperCast.getDisplayName();
  }
 else   if (slapper instanceof ConsoleCommandSender) {
    slapperName="String_Node_Str";
  }
 else {
    slapperName="String_Node_Str";
  }
  if (split.length == 1 || split.length == 2) {
    List<Player> matchedPlayers=plugin.getServer().matchPlayer(split[0]);
    String slappeeName=split[0];
    if (matchedPlayers.size() == 1) {
      if (split.length == 1) {
        slapPlayer(matchedPlayers.get(0),2,slapperName);
      }
 else {
        float force=Float.parseFloat(split[1]);
        if (force > 10) {
          force=10;
        }
 else         if (force <= 0) {
          force=0.1f;
        }
        slapPlayer(matchedPlayers.get(0),force,slapperName);
      }
    }
 else     if (matchedPlayers.isEmpty()) {
      slapper.sendMessage("String_Node_Str" + slappeeName + "String_Node_Str");
    }
 else     if (matchedPlayers.size() > 1) {
      slapper.sendMessage(slappeeName + "String_Node_Str");
    }
 else {
      slapper.sendMessage("String_Node_Str");
    }
    return true;
  }
 else {
    return false;
  }
}

Fixed version (ground truth):
@Override public boolean onCommand(CommandSender slapper,Command command,String label,String[] split){
  if (plugin.usePermissions) {
    if (!(plugin.permissionHandler.has((Player)slapper,"String_Node_Str"))) {
      slapper.sendMessage(ChatColor.RED + "String_Node_Str");
      return true;
    }
  }
 else   if (!(slapper.isOp())) {
    slapper.sendMessage(ChatColor.RED + "String_Node_Str");
    return true;
  }
  String slapperName;
  if (slapper instanceof Player) {
    Player slapperCast=(Player)slapper;
    slapperName=slapperCast.getDisplayName();
  }
 else   if (slapper instanceof ConsoleCommandSender) {
    slapperName="String_Node_Str";
  }
 else {
    slapperName="String_Node_Str";
  }
  if (split.length == 1 || split.length == 2) {
    List<Player> matchedPlayers=plugin.getServer().matchPlayer(split[0]);
    String slappeeName=split[0];
    if (matchedPlayers.size() == 1) {
      if (split.length == 1) {
        slapPlayer(matchedPlayers.get(0),2,slapperName);
      }
 else {
        float force;
        try {
          force=Float.parseFloat(split[1]);
        }
 catch (        NumberFormatException e) {
          slapper.sendMessage("String_Node_Str");
          return true;
        }
        if (force > 10) {
          force=10;
        }
 else         if (force <= 0) {
          force=0.1f;
        }
        slapPlayer(matchedPlayers.get(0),force,slapperName);
      }
    }
 else     if (matchedPlayers.isEmpty()) {
      slapper.sendMessage("String_Node_Str" + slappeeName + "String_Node_Str");
    }
 else     if (matchedPlayers.size() > 1) {
      slapper.sendMessage(slappeeName + "String_Node_Str");
    }
 else {
      slapper.sendMessage("String_Node_Str");
    }
    return true;
  }
 else {
    return false;
  }
}