jodd-db/src/main/java/jodd/db/type/NullAwareSqlType.java
@Override
	public <E> E readValue(final ResultSet rs, final int index, final Class<E> destinationType, final int dbSqlType) throws SQLException {
		T t = get(rs, index, dbSqlType);
		if ((t == null) || (rs.wasNull())) {
			return null;
		}
		return prepareGetValue(t, destinationType);
	}
@Override
	public <E> E readValue(final ResultSet rs, final int index, final Class<E> destinationType, final int dbSqlType) throws SQLException {
		T t = get(rs, index, dbSqlType);
		if ((t == null) || (rs.wasNull())) {
			return null;
		}
		return prepareGetValue(t, destinationType);
	}
Detects if there was a <code>null</code> reading and returns <code>null</code> if it was.
Result set returns default value (e.g. 0) for many getters, therefore it detects if it was
a null reading or it is a real value.