add maven compiler version to avoid the warnings
fix problem of having validation on the sheet but get the null result when fetching it
check getRGBString(font.getColor()) to make sure that the result is not null before using it
test shoudl validate XML against schema
dont add the whole validation element if the formular is null
fix merge conflict
fix merge conflict
updated to use a patched version of poi 3.9
Little reformatting