ADDITIONAL SYSTEM INFORMATION :
Windows 10. Fails on Java 9.0.1 and newer, not sure when it was introduced. No problem under Java 8.

A DESCRIPTION OF THE PROBLEM :
For java source files in a OneDrive folder with the On-Demand setting on (only available and the default on recent versions of Windows 10), javac will not compile the files, and reports "not a file".

REGRESSION : Last worked in version 8u162

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Attempt to compile any Java file in a OneDrive folder with On-Demand turned on.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Expect file to compile.
ACTUAL -
javac reports "not a file", does not compile. Here are results of a test with Java 9.0.1 and 1.8.0_161:

C:\Users\larry\OneDrive>"C:\Program Files\Java\jdk-9.0.1\bin\javac" Test.java
javac: not a file: Test.java
Usage: javac <options> <source files>
use --help for a list of possible options

C:\Users\larry\OneDrive>"C:\Program Files\Java\jdk1.8.0_161\bin\javac" Test.java


---------- BEGIN SOURCE ----------
public class Test {
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Turn off On-Demand in OneDrive settings or copy files in/out of a non-OneDrive folder to work with them.


FREQUENCY : always