PostmanService postmanService = new PostmanService("<<POSTMAN_SERVER_URL>>", "API_KEY");

PostmanMessage message = new PostmanMessageBuilder()
                .from("no-reply@my-domain.com")
                .to("email@company.com")
                .cc("email@company.com")
                .bcc("email@company.com")
                .withSubject("Testing with attachments")
                .withPlainBody("Please view this email in a modern email client!")
                .withHtmlBody("<html><h1>html body</h1><h2>Please check your attachments!</h2></html>")
                .withTag("tag")
                .addAttachment(new Attachment("test-csv.csv", "application/octet-stream", attachmentByte))
                .build();

postman.sendMessage(message);

Embedded images

If you want to use embedded image simply add it with

.addEmbeddedImage(new EmbeddedImage("cidReference", "image/png", googleLogo))

And reference if in the html body of your email with

<img src="cid:google" width="140">

You can put Base64 encoded documents for attachments and embedded image or the byte[] of your document in the methods addAttachment and addEmbeddedImage