A DESCRIPTION OF THE PROBLEM :
When calling ImageIO.write(..) for a JPEG with a thumbnail: you may write a corrupt JPEG file depending on the dimensions.

In the attached test case: dimensions of 100x218 pass, but 100x219 fail.

(I'm guessing the problem is that 100*219*3 = 65700, which exceeds the ~65536 size limit for a JPEG segment.)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the attached test code

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Ideally the console should indicate that both tests pass. This may be tricky, though, because writing a valid JPEG file here may require automatically switching from the RGB-encoded thumbnail to a JPEG-encoded thumbnail.

Or an alternative expected behavior might be:
The act of calling `ImageIO.write(..)` should fail with an Exception. (Ideally without writing to the OutputStream at all.) It is important to let the caller know that their image data is NOT safe/saved.
ACTUAL -
An exception appears for the larger thumbnail:
```
javax.imageio.IIOException: Unsupported JPEG process: SOF type 0xc8
at java.desktop/com.sun.imageio.plugins.jpeg.JPEGImageReader.readImageHeader(Native Method)
at java.desktop/com.sun.imageio.plugins.jpeg.JPEGImageReader.readNativeHeader(JPEGImageReader.java:739)
at java.desktop/com.sun.imageio.plugins.jpeg.JPEGImageReader.checkTablesOnly(JPEGImageReader.java:354)
at java.desktop/com.sun.imageio.plugins.jpeg.JPEGImageReader.gotoImage(JPEGImageReader.java:504)
at java.desktop/com.sun.imageio.plugins.jpeg.JPEGImageReader.getImageMetadata(JPEGImageReader.java:1136)
at java.desktop/com.sun.imageio.plugins.jpeg.JPEGImageReader.getNumThumbnails(JPEGImageReader.java:1652)
at WriteJPEGThumbnailTest.run(WriteJPEGThumbnailTest.java:79)
at WriteJPEGThumbnailTest.main(WriteJPEGThumbnailTest.java:54)
```

---------- BEGIN SOURCE ----------
import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.ImageWriter;
import javax.imageio.stream.ImageInputStream;
import javax.imageio.stream.ImageOutputStream;
import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.Arrays;
import java.util.Iterator;

public class WriteJPEGThumbnailTest {

    private static void assertEquals(int expected, int observed) {
        if (expected != observed) {
            throw new Error("expected " + expected + ", but observed " + observed);
        }
    }
    public static void main(String[] args) throws Exception {
        boolean b1 = new WriteJPEGThumbnailTest(100, 218).run();
        boolean b2 = new WriteJPEGThumbnailTest(100, 219).run();
        if (!(b1 && b2))
            System.err.println("Test failed");
    }

    final int thumbWidth, thumbHeight;

    public WriteJPEGThumbnailTest(int thumbWidth, int thumbHeight) {
        this.thumbWidth = thumbWidth;
        this.thumbHeight = thumbHeight;
    }

    public boolean run() throws Exception {
        System.out.println("Testing thumbnail " + thumbWidth + "x" + thumbHeight + "...");
        try {
            byte[] jpegData;
            BufferedImage thumbnail;
            try (ByteArrayOutputStream byteOut = new ByteArrayOutputStream()) {
                thumbnail = writeImage(byteOut);
                jpegData = byteOut.toByteArray();
            }

            ImageReader reader = getJPEGImageReader();
            ImageInputStream stream = ImageIO.createImageInputStream(new ByteArrayInputStream(jpegData));
            reader.setInput(stream);
            assertEquals(1, reader.getNumThumbnails(0));
            assertEquals(thumbnail.getWidth(), reader.getThumbnailWidth(0, 0));
            assertEquals(thumbnail.getHeight(), reader.getThumbnailHeight(0, 0));

            BufferedImage readThumbnail = reader.readThumbnail(0, 0);
            for (int y = 0; y < readThumbnail.getHeight(); y++) {
                for (int x = 0; x < readThumbnail.getWidth(); x++) {
                    assertEquals(thumbnail.getRGB(x, y), readThumbnail.getRGB(x, y));
                }
            }
            System.out.println("\tTest passed");
        } catch(Exception e) {
            e.printStackTrace();
            return false;
        }
        return true;
    }

    private BufferedImage writeImage(OutputStream out) throws IOException {
        BufferedImage thumbnail = createImage(thumbWidth, thumbHeight);
        BufferedImage bi = createImage(thumbnail.getWidth() * 10, thumbnail.getHeight() * 10);

        ImageWriter writer = ImageIO.getImageWritersByFormatName("jpeg").next();

        try (ImageOutputStream outputStream = ImageIO.createImageOutputStream(out)) {
            writer.setOutput(outputStream);

            // Write the main image
            IIOImage img = new javax.imageio.IIOImage(bi, Arrays.asList(thumbnail), null);
            writer.write(null, img, null);

            writer.dispose();
        }
        return thumbnail;
    }

    private static BufferedImage createImage(int width, int height) {
        BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g = bi.createGraphics();
        double sx = ((double)width) / 1000.0;
        double sy = ((double)height) / 1000.0;
        g.transform(AffineTransform.getScaleInstance(sx, sy));
        g.setColor(Color.red);
        g.fillRect(0,0,100,100);
        g.setColor(Color.green);
        g.fillRect(900,0,900,100);
        g.setColor(Color.orange);
        g.fillRect(0,900,100,100);
        g.setColor(Color.magenta);
        g.fillRect(900,900,100,100);
        g.dispose();
        return bi;
    }

    private static ImageReader getJPEGImageReader() {
        Iterator<ImageReader> readers = ImageIO.getImageReadersByFormatName("jpeg");
        ImageReader reader;
        while(readers.hasNext()) {
            reader = readers.next();
            if(reader.canReadRaster()) {
                return reader;
            }
        }
        return null;
    }
}
---------- END SOURCE ----------