Driver version

7.3.0.jre-8-preview

SQL Server version

Microsoft SQL Server 2017 (RTM-CU15) (KB4498951) - 14.0.3162.1 (X64)
May 15 2019 19:14:30
Copyright (C) 2017 Microsoft Corporation
Developer Edition (64-bit) on Linux (Ubuntu 16.04.6 LTS)

Client Operating System

Mac OS X

JAVA/JVM version

1.8.0

Table schema

CREATE TABLE points (location GEOGRAPHY)

Problem description

STAsBinary() returns null for single point values.
The problem is STAsBinary() always returns value of wkbNoZM field but if a Geography variable represents a single point then serializeToWkb writes to wkb field and wkbNoZM stays null. Here's relevant code in the driver

        if (isSinglePoint || isSingleLineSegment) {
            wkb = buf.array();
            return;
        }

JDBC trace logs

Reproduction code

        Geography point = Geography.parse("POINT (10 20)");

        byte[] wkb = point.STAsBinary();

        System.out.println(wkb);