Not sure if a bug, just in case:

was checked with Quartz Debug emulation for HiDPI.

please run the following code:

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.io.File;
import javax.imageio.ImageIO;


public class Test extends Frame {

    static Image img;
    public Test() { EventQueue.invokeLater(this::CreateUI); }

    private static final int sz = 100;
    private static final String name1x = "image.png";
    private static final String name2x = "image@2x.png";

    static void generateImages() throws Exception {
        if (!new File(name1x).exists()) { generateImage(1); }
        if (!new File(name2x).exists()) { generateImage(2); }
    }

    static void generateImage(int scale) throws Exception {
        BufferedImage image = new BufferedImage(scale * sz, scale * sz, BufferedImage.TYPE_INT_RGB);
        Graphics g = image.getGraphics();
        g.setColor(scale == 1 ? Color.GREEN : Color.BLUE);
        g.fillRect(0, 0, scale * sz, scale * sz);
        File file = new File(scale == 1 ? name1x : name2x);
        ImageIO.write(image, "png", file);
    }

    private void CreateUI() {
        addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) { dispose(); }
        });

        setSize(300, 300);
        setVisible(true);
    }

    @Override
    public void paint(Graphics gr) {
        Graphics2D g = (Graphics2D) gr;
        if (g != null) {
            File imageFile = new File(name1x);
            //File imageFile = new File("image.tiff");
            String fileName = imageFile.getAbsolutePath();
            img = Toolkit.getDefaultToolkit().getImage(fileName);
            g.drawImage(img, 0, 0, this);
        }
    }

    public static void main(String[] args) throws Exception {
        System.out.println(System.getProperty("java.vm.version"));
        Robot r = new Robot();
        generateImages();
        r.delay(1000);
        new Test();
    }
}


The behavior is as expected (blue square for HiDPI, green - for the default display resolution).


Then please merge "image.png" + "image@2x.png" pair using tiffutil and then remove png-files:
tiffutil -cathidpicheck image.png image@2x.png -out image.tiff
rm *.png

Please return to the test code and replace
"File imageFile = new File(name1x);"
with
"File imageFile = new File("image.tiff");"
and comment out generateImages call in main. No image is drawn when running (as Toolkit.getImage() does not support TIFF for now). JDK9 b77 is used; OS: Mac OS X 10.10.3

The tiff image is correct and contains two images (checked using macosx Preview).


The following cocoa code displays the tiff file correctly (blue/green square, depending on is HiDPI emulation id on or off):

echo '#import <Cocoa/Cocoa.h>
int main() {
    [NSAutoreleasePool new];
    [NSApplication sharedApplication];
    [NSApp setActivationPolicy:NSApplicationActivationPolicyRegular];
    id appName = [[NSProcessInfo processInfo] processName];

    id img = [NSImage imageNamed:@"image.tiff"];

    NSRect frame = NSMakeRect(0, 0, 400, 400);
    NSUInteger styleMask = NSTitledWindowMask;
    NSRect rect = [NSWindow contentRectForFrameRect:frame styleMask:styleMask];
    id window = [[NSWindow alloc] initWithContentRect:rect styleMask:styleMask backing:NSBackingStoreBuffered defer:false];

    id imView = [[NSImageView alloc] initWithFrame:NSMakeRect(0, 0, 400, 400)];
    [imView setImage:img];
    [imView setImageScaling:NSImageScaleProportionallyDown];

    [window setContentView:imView];
    [window makeKeyAndOrderFront:nil];
    [window cascadeTopLeftFromPoint:NSMakePoint(20, 20)];
    [window setTitle:appName];
    [NSApp activateIgnoringOtherApps:YES];
    [NSApp run];
    return 0;
}' | gcc -framework Cocoa -x objective-c -o runTest - ; ./runTest