Graphics2D into BufferedImage

I have found many ways to turn a image into a Graphics2d, but I am not sure how to turn my Graphics2d into a BufferedImage. How would I do this.

For example:

Graphics2D SomeGraphics;
SomeGraphics.drawImage(image, x,y,size,size);
SomeGraphics.fillRect(x,y,size,size);

Now how would I convert that Graphics into a Buffered Image?