HI MIchal,
i tried the instructions at this link you suggested below but i am getting errors- i am wondering if it has to do with the OR 2.6 beta with new drools version or Java version 8
https://openremote.github.io/archive-dotorg/forums/22872974.html
below is the copy of the rule and the error messages- i hope its something simple 
Any help is greatly appreciated.
I have 2 drl files in the rules folder - one with working set of rules and other with the rule for email for testing.
//trial email with orcbeta2.6
package org.openremote.controller.model.event
global org.openremote.controller.statuscache.CommandFacade execute;
global org.openremote.controller.statuscache.SwitchFacade switches;
global org.openremote.controller.statuscache.LevelFacade levels;
import org.openremote.controller.protocol.Event;
import java.util.Properties;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
// email notifications
rule “Send mail”
when
Switch ( source == “Send mail sensor”, value == “on”)
then
execute.command (“Send mail OFF”);
final String username = “orc@gmail.com”;
final String password = “mypassword”;
Properties props = new Properties();
props.put(“mail.smtp.host”, “smtp.gmail.com”);
props.put(“mail.smtp.socketFactory.port”, “465”);
props.put(“mail.smtp.socketFactory.class”,“javax.net.ssl.SSLSocketFactory”);
props.put(“mail.smtp.auth”, “true”);
props.put(“mail.smtp.port”, “465”);
Session session = Session.getInstance(props,
new javax.mail.Authenticator() {
protected PasswordAuthentication getPasswordAuthentication() {
return new PasswordAuthentication(username, password);
}
});
try {
Message message = new MimeMessage(session);
message.setFrom(new InternetAddress(“orc@gmail.com”));
message.setRecipients(Message.RecipientType.TO,
InternetAddress.parse(“orc@gmail.com”));
message.setSubject(“trial”);
message.setText(“triall triall”);
Transport.send(message);
System.out.println(“Mail sent”);
} catch (MessagingException e) {
throw new RuntimeException(e);
}
end
ERROR messages:
DEBUG 2017-03-12 22:16:12,460 : Starting event processor: Drools Rule Engine
DEBUG 2017-03-12 22:16:12,583 : Adding Rule ‘trial_modeler_rules.drl’…
DEBUG 2017-03-12 22:16:12,584 : Adding Rule ‘modeler_rules.drl’…
INFO 2017-03-12 22:16:21,149 : Starting device discovery service…
DEBUG 2017-03-12 22:16:21,150 : checking for discovered devices…
ERROR 2017-03-12 22:16:22,581 : Rule definition ‘trial_modeler_rules.drl’ could not be deployed. See errors below.
ERROR 2017-03-12 22:16:22,584 : Rule Compilation error Only a type can be imported. javax.mail.PasswordAuthentication resolves to a package
Only a type can be imported. javax.mail.internet.InternetAddress resolves to a package
Only a type can be imported. javax.mail.Message resolves to a package
Only a type can be imported. javax.mail.Transport resolves to a package
Only a type can be imported. javax.mail.MessagingException resolves to a package
Only a type can be imported. javax.mail.Session resolves to a package
Only a type can be imported. javax.mail.internet.MimeMessage resolves to a package
Session cannot be resolved to a type
Session cannot be resolved
javax.mail.Authenticator cannot be resolved to a type
Message cannot be resolved to a type
MimeMessage cannot be resolved to a type
InternetAddress cannot be resolved to a type
Message.RecipientType.TO cannot be resolved to a type
InternetAddress cannot be resolved
Transport cannot be resolved
MessagingException cannot be resolved to a type
ERROR 2017-03-12 22:16:22,586 : Error importing : ‘javax.mail.PasswordAuthentication’
ERROR 2017-03-12 22:16:22,586 : Error importing : ‘javax.mail.internet.MimeMessage’
ERROR 2017-03-12 22:16:22,587 : Error importing : ‘javax.mail.MessagingException’
ERROR 2017-03-12 22:16:22,588 : Error importing : ‘javax.mail.internet.InternetAddress’
ERROR 2017-03-12 22:16:22,588 : Error importing : ‘javax.mail.Session’
ERROR 2017-03-12 22:16:22,589 : Error importing : ‘javax.mail.Transport’
ERROR 2017-03-12 22:16:22,590 : Error importing : ‘javax.mail.Message’
INFO 2017-03-12 22:16:24,056 : Added rule definition ‘modeler_rules.drl’ to knowledge.
INFO 2017-03-12 22:16:33,971 : Started event processor : Drools Rule Engine