JNA battery status functions not working under Windows 10 (Java)

Question

I've imported the JNA libary for usage in my Java project. I have this Kernel32 class that allows me to use the library in my project:

package winsot;

import java.util.ArrayList;
import java.util.List;

import com.sun.jna.Native;
import com.sun.jna.Structure;
import com.sun.jna.win32.StdCallLibrary;

public interface Kernel32 extends StdCallLibrary {

public Kernel32 INSTANCE = (Kernel32) Native.loadLibrary("Kernel32", Kernel32.class);

/**
 * @see http://msdn2.microsoft.com/en-us/library/aa373232.aspx
 */
public class SYSTEM_POWER_STATUS extends Structure {
    public byte ACLineStatus;
    public byte BatteryFlag;
    public byte BatteryLifePercent;
    public byte Reserved1;
    public int BatteryLifeTime;
    public int BatteryFullLifeTime;

    @Override
    protected List<String> getFieldOrder() {
        ArrayList<String> fields = new ArrayList<String>();
        fields.add("ACLineStatus");
        fields.add("BatteryFlag");
        fields.add("BatteryLifePercent");
        fields.add("Reserved1");
        fields.add("BatteryLifeTime");
        fields.add("BatteryFullLifeTime");
        return fields;
    }

    /**
     * The AC power status
     */
    public String getACLineStatusString() {
        switch (ACLineStatus) {
            case (0): return "Offline";
            case (1): return "Online";
            default: return "Unknown";
        }
    }

    /**
     * The battery charge status
     */
    public String getBatteryFlagString() {
        switch (BatteryFlag) {
            case (1): return "High, more than 66 percent";
            case (2): return "Low, less than 33 percent";
            case (4): return "Critical, less than five percent";
            case (8): return "Charging";
            case ((byte) 128): return "No system battery";
            default: return "Unknown";
        }
    }

    /**
     * The percentage of full battery charge remaining
     */
    public String getBatteryLifePercent() {
        return (BatteryLifePercent == (byte) 255) ? "Unknown" : BatteryLifePercent + "%";
    }

    /**
     * The number of seconds of battery life remaining
     */
    public String getBatteryLifeTime() {
        return (BatteryLifeTime == -1) ? "Unknown" : BatteryLifeTime + " seconds";
    }

    /**
     * The number of seconds of battery life when at full charge
     */
    public String getBatteryFullLifeTime() {
        return (BatteryFullLifeTime == -1) ? "Unknown" : BatteryFullLifeTime + " seconds";
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("ACLineStatus: " + getACLineStatusString() + "\n");
        sb.append("Battery Flag: " + getBatteryFlagString() + "\n");
        sb.append("Battery Life: " + getBatteryLifePercent() + "\n");
        sb.append("Battery Left: " + getBatteryLifeTime() + "\n");
        sb.append("Battery Full: " + getBatteryFullLifeTime() + "\n");
        return sb.toString();
    }
}

/**
 * Fill the structure.
 */
public int GetSystemPowerStatus(SYSTEM_POWER_STATUS result);
}

I am trying to retrieve battery status details, so I run this code in another class:

Kernel32.SYSTEM_POWER_STATUS batteryStatus = new Kernel32.SYSTEM_POWER_STATUS(); //new instance of class
        System.out.println(batteryStatus);

However it seems that the JNA library is unable to access the battery information from Windows, as System.out.println(batteryStatus) returns this:

ACLineStatus: Offline
Battery Flag: Unknown
Battery Life: 0%
Battery Left: 0 seconds
Battery Full: 0 seconds

Does the JNA library no longer work under Windows 10, or am I missing something?

Thanks.