Allow primitive columns to be declared to accept NULL

If a primitive column appears as a leaf-level column in a nested
field the field itself may be set to null in Java, causing the
SQL value to be set to null for the primitive type, thus we must
support null values on the leaf-level columns, even if the Java
primitive type it represents doesn't know how to store a null.

Signed-off-by: Shawn O. Pearce <sop@google.com>
5 files changed