1. This works:
   

    public boolean addtoPlayerList(Player player){
   String name=player.getName();
    if (PlayerNumber>=MaximumPlayer) {return false;}//人数超过则返回错误
   else {
       if(isInList(name)==false){
           this.PlayerList[PlayerNumber]=name;
           getLogger().info("玩家:"+name+"已被添加至游戏列表。");
           //Bukkit.getPlayer(name).sendMessage("玩家:"+name+"已被添加至游戏列表。");
           PlayerNumber++;
           return true;
       }//不然就把名单上面下一位给加上传过来的玩家
       else{
          getLogger().info("玩家"+name+"已存在列表中");
          Bukkit.getPlayer(name).sendMessage("玩家"+Bukkit.getPlayer(name)+"已存在列表中");
         return false;
       }
   }
   }
   

   
   This don’t:
   

   public boolean addtoPlayerList(Player player){
   if (PlayerNumber>=MaximumPlayer) {return false;}//人数超过则返回错误
   else {
       if(isInList(player)==false){
           PlayerList[PlayerNumber]=(String)player.getName();//这个方法和下面那个是重载关系，都会出错，出错相同
           getLogger().info("玩家:"+player.getName()+"已被添加至游戏列表。");
           player.sendMessage("玩家:"+player.getName()+"已被添加至游戏列表。");
           return true;
       }//不然就把名单上面下一位给加上传过来的玩家
       else{
          getLogger().info("玩家"+player.getName()+"已存在列表中");
          player.sendMessage("玩家"+player.getName()+"已存在列表中");
          return false;
       }
   }
   }

   
   Why?
   
   
   2016/12/5: As I believed, this is the same problem with the one below.
   
   
2. ~~Bukkit.getPlayer(name) will report a NullPointerException when using. Why?
   
   

2016/12/15:
Let me simple this down to this:
Using Bukkit.getPlayer(args[0]) itself as a player instance will give a NullPointerException when using. But when I use

Player player=Bukkit.getPlayer(args[0]);

first and then use the player instance instead, everything works. Why?(I asked a few friends but still unsolved)
~~
==Solved: When I was calling the method, the player was offline so it returns a null pointer. Also, I foget to check it so the error occurs. ==

1. When I access a text file on my website generated by the pipeline or redirected output of a command or a program, all the \n have to be replaces with
   to keep the form. How to make it more convenient?
   ==Possible solution: use view:sourcecode when browsing==
   
   

2016/12/12
4.When using any types of audio players in my raspberry pi to play music, I found when I keep playing in a terminal, it will report a “audio device stuck” error and just stop. Even ^C don’t work on it. Why?


2016/12/19
5.I am trying to install Ubuntu on the second disk of my computer. But I think the boot priority is locked on my computer so I cannot boot from the second disk as long as I have a system on the first one. I have to go to recovery mode to manually make the computer boot from the second disk.
What should I do…
2016/12/20
Possible soluction from @Superboot:
== d0048: Install grub onto the MBR of the first disk, and it will give you a list of OSs to boot at boot time.

d0048: To be more specific, I would boot into your ubuntu install (you said you could from recovery mode), and run: sudo grub-install /dev/sdb. Be sure to check that /dev/sda.==
2016/12/22
Looks like my computer locked my start up sequence. I tried to install a lower version bios as the custom service guy. But not working. Also, trying on installing grub on each disk and each partition is not working to. So I ask the service guy again and this time he told me that the booting partition is loaded on the second disk and need to be erased manually. Till now, I don’t feels like worth to do it so I guess I will just press F9 before actually start booting.

==Solved:== Install a software called easyuefi. It couldn’t delete but do successfully disabled the windows loader. Now grub will be entered at first. 2017/2/13

6.The school will shutoff the Internet access after 10:30 pm. But if it’s connected beforehand with Ethernet, it won’t be shut as long as the device keeps connected. But if the device disconnected after 10:30 pm, it cannot connect again.

######why?

7.What’s the relationship between android build tool version, android sdk version, android api level, grandle version, grandle plugin version and those version of dependencies.
2017/3/14

#####If you have any solution, please comment below or contact me through d0048@china.com.cn#####