jodd-mail/src/main/java/jodd/mail/ReceivedEmail.java
private ReceivedEmail addAttachment(final Part part, final InputStream content, final File attachmentStorage) throws MessagingException, IOException {
		final EmailAttachmentBuilder builder = addAttachmentInfo(part);
		builder.content(content, part.getContentType());
		if (attachmentStorage != null) {
			String name = messageId + "-" + (this.attachments().size() + 1);
			return storeAttachment(builder.buildFileDataSource(name, attachmentStorage));
		}
		return storeAttachment(builder.buildByteArrayDataSource());
	}
private ReceivedEmail addAttachment(final Part part, final InputStream content, final File attachmentStorage) throws MessagingException, IOException {
		final EmailAttachmentBuilder builder = addAttachmentInfo(part);
		builder.content(content, part.getContentType());
		if (attachmentStorage != null) {
			String name = messageId + "-" + (this.attachments().size() + 1);
			return storeAttachment(builder.buildFileDataSource(name, attachmentStorage));
		}
		return storeAttachment(builder.buildByteArrayDataSource());
	}
Adds received attachment.

@param part    {@link Part}.
@param content Content as {@link InputStream}.
@return this
@see #attachment(EmailAttachment)