@Override
    public Double getValue(ResultSet rs, int startIndex) throws SQLException {
        double val = rs.getDouble(startIndex);
        return rs.wasNull() ? null : val;
    }
{@code DoubleType} maps Double to Double on the JDBC level

@author tiwe
querydsl-sql/src/main/java/com/querydsl/sql/types/DoubleType.java