Question

Sometimes, I want to use an ObjectOutputStream to write something to a file or sending a little image over the network. But BufferedImage and many other classes don’t implement java.io.Serializable and then the Stream cancels writing. Is there a way avoid that?

Thanks, Martijn

Answer 1

Only objects that support the
java.io.Serializable interface can be
written to streams.

— ObjectOutputSteam docs

However, you could avoid all this by using one of the classes in javax.imageio. Specifically the ImageIO.write(RenderedImage, String, OutputStream) method, because BufferedImage implements RenderedImage. You can then read it back out with ImageIO.read(InputStream), which returns a BufferedImage.

You’ll probably want a different OutputSteam type, though. In addition to the normal OutputStreams, there are several special ImageOutputStreams.

Edit: I missed this before:
To get a list of valid strings for the middle argument, you can call ImageIO.getWriterFormatNames()