To compile java files within Directory including subdirectory

There is no direct way to do it.

Alternatives:
1. using Build tool like Maven, Ant etc or using Batch scripts.
2. using command line,

>dir /b /s *.java >> files.txt

Dir to Display a list of files and subfolders
/b for Bare format (no heading, file sizes or summary).
/s for include all subfolders.
>> for print the output in to a file

Then type: javac @files.txt