Hi Rakesh,
Thank you for posting your inquiry.
You can use the following sample code to convert a message to HTML. Please try it at your end and let us know if you need any further assistance in this regard.
Sample Code:
MailMessage msg = MailMessage.load(dataDir + “Message.msg”);
msg.save(dataDir + “SavingMessageAsHTML_out1.html”, SaveOptions.getDefaultHtml());
//or
MailMessage eml = MailMessage.load(dataDir + “test.eml”);
HtmlSaveOptions options = SaveOptions.getDefaultHtml();
options.setEmbedResources(false);
options.setHtmlFormatOptions(HtmlFormatOptions.WriteHeader | HtmlFormatOptions.WriteCompleteEmailAddress);
eml.save(dataDir + “SavingMessageAsHTML_out2.html”, options);