\ is an escape character in java, so in this case you need
C:\\neha\\files
and same for getFilesInDir("C:\\neha"); in DirectoryTest.java
now even if you specify the correct path its possible that no files exist in the specified in the given directory , so you need to put check before continuing the process
Neha,
In future, please use code tags.
I have edited your original post to use code tags, and as you can see it makes the code easier to read an understand. It even displays the line numbers !