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I am uploading images using servlet. To perform resize operations i am converting InputStream to BufferedImage. Now i want to save it in mongoDB. Since, i am new to mongoDB as far as i know, GridFS takes InputStream.

So, is there any way to convert BufferedImage to InputStream?

BufferedImage ➙ ByteArrayOutputStream ➙ byte[] ➙ ByteArrayInputStream

Use the ImageIO.write method to make a BufferedImage (which is a RenderedImage ) into a ByteArrayOutputStream . From there get a byte array ( byte[] ), feeding that into an InputStream of type ByteArrayInputStream .

ByteArrayOutputStream os = new ByteArrayOutputStream();
ImageIO.write(buffImage, "jpeg", os);                          // Passing: ​(RenderedImage im, String formatName, OutputStream output)
InputStream is = new ByteArrayInputStream(os.toByteArray());
Both the ByteArrayOutputStream and InputStream implement AutoCloseable. So you can conveniently have those closed automatically by using try-with-resources syntax. 
                Tried this, got a compile error on the third line: "The method ByteArrayInputStream(byte[]) is undefined for the type" What does that mean?
– Möoz
                Dec 19, 2014 at 0:48
                Have you made the import correctly. The constructor is correct. docs.oracle.com/javase/7/docs/api/java/io/…
– Sorter
                Dec 19, 2014 at 6:38
                Doesn't anything need to be closed anywhere? I'm not asking to be mean, I simply dont know ;)
– Nicofisi
                Oct 31, 2017 at 18:15
                @Nicofisi Both ByteArrayOutputStream & InputStream implement AutoCloseable. So you can use try-with-resources syntax to conveniently and automatically close those resources whether or not exceptions are thrown.
– Basil Bourque
                Oct 26, 2019 at 18:15
                +1. and this method copies the data not once but twice! once when writing to ByteArrayOutputStream and then again by converting it into a byte array when toByteArray() is called.
– morpheus
                May 21, 2016 at 0:37
First of all you must get your "bytes":
byte[] buffer = ((DataBufferByte)(bufferedImage).getRaster().getDataBuffer()).getData();
And then use ByteArrayInputStream(byte[] buf) constructor to create your InputStream;
                It's funny that this code snippet works much more efficiently than the approved one, although not as elegant
– Nikita Kobtsev
                Mar 26, 2022 at 22:11
                But it is worth noting that this will only work with images where byte[] is used to represent each pixel
– Nikita Kobtsev
                Mar 26, 2022 at 23:06
By overriding the method toByteArray(), returning the buf itself (not copying), you can avoid memory related problems. This will share the same array, and not creating another of the correct size. The important thing is to use the size() method in order to control the number of valid bytes into the array.
final ByteArrayOutputStream output = new ByteArrayOutputStream() {
    @Override
    public synchronized byte[] toByteArray() {
        return this.buf;
ImageIO.write(image, "png", output);
return new ByteArrayInputStream(output.toByteArray(), 0, output.size());