This is a good for loop example:
Command line usage:
for /f %f in ('dir /b c:\') do echo %f
Batch file usage:
for /f %%f in ('dir /b c:\') do echo %%f
if the directory contains files with space in the names, you need to change the delimiter the for /f command is using. for example, you can use the pipe char.
for /f "delims=|" %%f in ('dir /b c:\') do echo %%f
If the directory name itself has a space in the name, you can use the usebackq option on the for:
for /f "usebackq delims=|" %%f in (`dir /b "c:\program files"`) do echo %%f
And if you need to use output redirection or command piping, use the escape char (^):
for /f "usebackq delims=|" %%f in (dir /b "c:\program files" ^|
findstr /i microsoft
) do echo %%f
It shows both command line + batch for loop examples. Then you will have the filenames and can just run some commands on those filenames like javac and java.
Just try to break it down to small tasks:
Get list of files (all or just .class)
Loop through each file and call javac and java on them
Google is your best friend - search for "DOS batch" + what you need