Command to run xtend batch compiler is:
java -jar path/to/xtend_windows_fix.jar -cp path/to/xtend_windows_fix.jar path/to/input -d output/path
path/to/input: Directory containing all the .xtend files.
fixed the org.eclipse.xtend.lib.macro.file.Path.getParent(Path.java:129) problem which is claimed to be fixed for windows,
but not fixed!
for detail please follow: https://bugs.eclipse.org/bugs/show_bug.cgi?id=421000