Source:
public void sendMail(EmailBean emailBean) throws SendMailException { File tempDir = null; try { MimeMessage message = new MimeMessage(mailSessionProvider.get()); Multipart contentPart = new MimeMultipart(); MimeBodyPart bodyPart = new MimeBodyPart(); bodyPart.setText(emailBean.getBody(), "UTF-8", getSubType(emailBean.getMimeType())); contentPart.addBodyPart(bodyPart); if (emailBean.getAttachments() != null) { tempDir = Files.createTempDir(); for (Attachment attachment : emailBean.getAttachments()) { byte[] attachmentContent = Base64.getDecoder().decode(attachment.getContent()); File attachmentFile = new File(tempDir, attachment.getFileName()); Files.write(attachmentContent, attachmentFile); MimeBodyPart attachmentPart = new MimeBodyPart(); attachmentPart.attachFile(attachmentFile); attachmentPart.setContentID("<" + attachment.getContentId() + ">"); contentPart.addBodyPart(attachmentPart); } } message.setContent(contentPart); message.setSubject(emailBean.getSubject(), "UTF-8"); message.setFrom(new InternetAddress(emailBean.getFrom(), true)); message.setSentDate(new Date()); message.addRecipients(Message.RecipientType.TO, InternetAddress.parse(emailBean.getTo())); if (emailBean.getReplyTo() != null) { message.setReplyTo(InternetAddress.parse(emailBean.getReplyTo())); } LOG.info( "Sending from to with subject {}", emailBean.getFrom(), emailBean.getTo(), emailBean.getSubject()); Transport.send(message); LOG.debug("Mail send"); } catch (Exception e) { LOG.error(e.getLocalizedMessage()); throw new SendMailException(e.getLocalizedMessage(), e); } finally { if (tempDir != null) { try { FileUtils.deleteDirectory(tempDir); } catch (IOException exception) { LOG.error(exception.getMessage()); } } } }

Target:
public void sendMail(EmailBean emailBean) throws SendMailException { File tempDir = null; try { MimeMessage message = new MimeMessage(mailSessionProvider.get()); Multipart contentPart = new MimeMultipart(); MimeBodyPart bodyPart = new MimeBodyPart(); bodyPart.setText(emailBean.getBody(), "UTF-8", getSubType(emailBean.getMimeType())); contentPart.addBodyPart(bodyPart); if (emailBean.getAttachments() != null) { tempDir = Files.createTempDir(); for (Attachment attachment : emailBean.getAttachments()) { byte[] attachmentContent = Base64.getDecoder().decode(attachment.getContent()); File attachmentFile = new File(tempDir, attachment.getFileName()); Files.write(attachmentContent, attachmentFile); MimeBodyPart attachmentPart = new MimeBodyPart(); attachmentPart.attachFile(attachmentFile); attachmentPart.setContentID("<" + attachment.getContentId() + ">"); contentPart.addBodyPart(attachmentPart); } } message.setContent(contentPart); message.setSubject(emailBean.getSubject(), "UTF-8"); message.setFrom(new InternetAddress(emailBean.getFrom(), true)); message.setSentDate(new Date()); message.addRecipients(Message.RecipientType.TO, InternetAddress.parse(emailBean.getTo())); if (emailBean.getReplyTo() != null) { message.setReplyTo(InternetAddress.parse(emailBean.getReplyTo())); } LOG.info( "Sending from to with subject {}", emailBean.getFrom(), emailBean.getTo(), emailBean.getSubject()); Transport.send(message); LOG.debug("Mail sent"); } catch (Exception e) { LOG.error(e.getLocalizedMessage()); throw new SendMailException(e.getLocalizedMessage(), e); } finally { if (tempDir != null) { try { FileUtils.deleteDirectory(tempDir); } catch (IOException exception) { LOG.error(exception.getMessage()); } } } }