As Java does not support unsigned integer types, the value types
are "rounded up" (an uint32 is represented as a long) but persisted
correctly (an uint32 is persisted as 4 bytes).
This CL makes a cast operation explicit so that the compiler
does not throw warning messages.
Co-authored-by: Dominic Battre <battre@chromium.org>
Co-authored-by: Derek Bailey <derekbailey@google.com>