Following the following document:
Android document - Messaging - Sending Email - Sending Email API - synchronous methods
http://backendless.com/documentation/messaging/android/messaging_sending_email_rest.htm
It seems that the following synchronous methods are missing from the latest CodeRunner and Android SDKs:
Android SDK version : Backendless SDK v1.10 for Android, released 08.11.2014.
CodeRunner™ v1.8 for Java, released 10.30.2014
// *******************************************
// synchronous methods
// *******************************************
public void Backendless.Messaging.sendTextEmail( String subject, String messageBody, List<String> recipients )
public void Backendless.Messaging.sendTextEmail( String subject, String messageBody, String recipient )
public void Backendless.Messaging.sendHTMLEmail( String subject, String messageBody, List<String> recipients )
public void Backendless.Messaging.sendHTMLEmail( String subject, String messageBody, String recipient )
public void Backendless.Messaging.sendEmail( String subject, BodyParts bodyParts, String recipient, List<String> attachments )
public void Backendless.Messaging.sendEmail( String subject, BodyParts bodyParts, String recipient )
public void Backendless.Messaging.sendEmail( String subject, BodyParts bodyParts, List<String> recipients, List<String> attachments )
The following is also listed in the example but doesn’t actually exist so cannot be executed:
Backendless.Messaging.sendHTMLEmail( “Dinner”, mailBody, recipients );
In conclusion, the sync APIs for sending e-mails seem to missing from the SDKs you can download but looking at the code on github it looks like they have been implemented.