Program: 86535
Project: 86535
Buggy source:
public static boolean sendToJail(String jailingplayer,CommandSender sender,Integer t){
  Player player=(Player)sender;
  FPlayer fplayer=FPlayers.i.get(sender.getName());
  Faction currentFaction=fplayer.getFaction();
  File currentJailFile=new File("String_Node_Str" + File.separator + "String_Node_Str"+ File.separator+ "String_Node_Str"+ File.separator+ "String_Node_Str"+ currentFaction.getId());
  World world;
  Player jplayer=server.getPlayer(jailingplayer);
  FPlayer fjplayer=FPlayers.i.get(jplayer);
  if (!fjplayer.getFactionId().equals(fplayer.getFactionId())) {
    fplayer.msg("String_Node_Str");
    return false;
  }
  if (currentJailFile.exists()) {
    try {
      String JailData=new Scanner(currentJailFile).useDelimiter("String_Node_Str").next();
      String[] jail_data=JailData.split("String_Node_Str");
      double x=Double.parseDouble(jail_data[0]);
      double y=Double.parseDouble(jail_data[1]);
      double z=Double.parseDouble(jail_data[2]);
      float Y=Float.parseFloat(jail_data[3]);
      float p=Float.parseFloat(jail_data[4]);
      world=(World)server.getWorld(jail_data[5]);
      jplayer.teleport(new Location(world,x,y,z,Y,p));
      Faction f=Factions.i.get(jplayer.getName());
      File jailingFile=new File("String_Node_Str" + File.separator + "String_Node_Str"+ File.separator+ "String_Node_Str"+ File.separator+ "String_Node_Str"+ fjplayer.getFactionId()+ "String_Node_Str"+ jplayer.getName());
      if (!jailingFile.exists()) {
        FileWriter filewrite=new FileWriter(jailingFile,true);
        filewrite.flush();
        filewrite.write(t);
        sender.sendMessage(ChatColor.GREEN + jplayer.getName() + "String_Node_Str");
        player.sendMessage(ChatColor.RED + "String_Node_Str");
        filewrite.close();
      }
 else {
        sender.sendMessage(ChatColor.RED + jplayer.getName() + "String_Node_Str");
      }
    }
 catch (    Exception e) {
      e.printStackTrace();
      sender.sendMessage(ChatColor.RED + "String_Node_Str");
    }
  }
 else {
    sender.sendMessage(ChatColor.RED + "String_Node_Str");
  }
  return false;
}

Fixed version (ground truth):
public static boolean sendToJail(String jailingplayer,CommandSender sender,Integer t){
  Player player=(Player)sender;
  FPlayer fplayer=FPlayers.i.get(sender.getName());
  Faction currentFaction=fplayer.getFaction();
  File currentJailFile=new File("String_Node_Str" + File.separator + "String_Node_Str"+ File.separator+ "String_Node_Str"+ File.separator+ "String_Node_Str"+ currentFaction.getId());
  World world;
  Player jplayer=server.getPlayer(jailingplayer);
  FPlayer fjplayer=FPlayers.i.get(jplayer);
  if (!fjplayer.getFactionId().equals(fplayer.getFactionId())) {
    fplayer.msg("String_Node_Str");
    return false;
  }
  if (currentJailFile.exists()) {
    try {
      String JailData=new Scanner(currentJailFile).useDelimiter("String_Node_Str").next();
      String[] jail_data=JailData.split("String_Node_Str");
      double x=Double.parseDouble(jail_data[0]);
      double y=Double.parseDouble(jail_data[1]);
      double z=Double.parseDouble(jail_data[2]);
      float Y=Float.parseFloat(jail_data[3]);
      float p=Float.parseFloat(jail_data[4]);
      world=(World)server.getWorld(jail_data[5]);
      jplayer.teleport(new Location(world,x,y,z,Y,p));
      Faction f=Factions.i.get(jplayer.getName());
      File jailingFile=new File("String_Node_Str" + File.separator + "String_Node_Str"+ File.separator+ "String_Node_Str"+ File.separator+ "String_Node_Str"+ fjplayer.getFactionId()+ "String_Node_Str"+ jplayer.getName());
      if (!jailingFile.exists()) {
        FileWriter filewrite=new FileWriter(jailingFile,true);
        filewrite.flush();
        filewrite.write(t);
        sender.sendMessage(ChatColor.GREEN + jplayer.getName() + "String_Node_Str");
        filewrite.close();
      }
 else {
        sender.sendMessage(ChatColor.RED + jplayer.getName() + "String_Node_Str");
      }
    }
 catch (    Exception e) {
      e.printStackTrace();
      sender.sendMessage(ChatColor.RED + "String_Node_Str");
    }
  }
 else {
    sender.sendMessage(ChatColor.RED + "String_Node_Str");
  }
  return false;
}