linux 下写java程序出现了一个问题

当我在linux下用vi打开Test.java文件时

[root@localhost tmp]# vi Test.java

会出现如下信息：

E325: ATTENTION
Found a swap file by the name ".Test.java.swp"

         owned by: root   dated: Wed Dec  7 13:52:56 2011
         file name: /var/tmp/Test.java
         modified: YES
         user name: root   host name: localhost
         process ID: 26153 (still running)
While opening file "Test.java"
             dated: Wed Dec  7 14:00:46 2011
      NEWER than swap file!

(1) Another program may be editing the same file.
    If this is the case, be careful not to end up with two
    different instances of the same file when making changes.
    Quit, or continue with caution.

(2) An edit session for this file crashed.
    If this is the case, use ":recover" or "vim -r Test.java"
    to recover the changes (see ":help recovery").
    If you did this already, delete the swap file ".Test.java.swp"
    to avoid this message.
"Test.java" 11L, 237C
Press ENTER or type command to continue

原因是我之前有一次使用vi 操作Test.java文件时出现了异常中断，所以在当前目录下产生了一个.Test.java.swp文件

但是我使用ls命令查看该目录下，却发现没有这个文件，后来使用ls -a命令查看才知道Test.java.swp是一个隐藏文件。

注：以.开头的文件就是隐藏文件

当我把该隐藏文件删除后再次打开就没有上面的警告了。

[root@localhost tmp]# rm .Test.java.swp

rm: remove regular file `.Test.java.swp'? y

[root@localhost tmp]#