public InputStreamDataSource(InputStream inputStream) {
    this.inputStream = inputStream;
}

@Override
public InputStream getInputStream() throws IOException {
    return inputStream;
}

@Override
public OutputStream getOutputStream() throws IOException {
    throw new UnsupportedOperationException("Not implemented");
}

@Override
public String getContentType() {
    return "*/*";
}

@Override
public String getName() {
    return "InputStreamDataSource";
}

MimeBodyPart messageBodyPart = new MimeBodyPart();
messageBodyPart.setContent(message, "text/html");

// creates body part for the attachment
MimeBodyPart attachPart = new MimeBodyPart();
String attachFile = attachment.getName();

InputStream ipStream=null;
ipStream = attachment.getInputStream();
DataHandler dataHandler = new DataHandler(new InputStreamDataSource(ipStream));
attachPart.setDataHandler(dataHandler);
attachPart.setFileName(attachFile);

// adds parts to the multipart
multipart.addBodyPart(messageBodyPart);
multipart.addBodyPart(attachPart);

msg.setContent(multipart);
Transport.send(msg);