Sending a custom email from Script Console resulting in the following error:

java.util.ServiceConfigurationError: javax.mail.Provider: Provider com.sun.mail.imap.IMAPProvider not found 

However, this only happens on Jira 8.10.0+.

Steps to Reproduce

1. Install Jira 8.10.0+ and the latest version of ScriptRunner
2. Send an email using this script on Script Console
3. Hits "IMAPProvider class not found" error

Workaround

Manually add the class to the current thread with the code below as per this community post:

// Rest of the imports
import com.atlassian.mail.server.SMTPMailServer;

// Rest of the codes
ClassLoader threadClassLoader = Thread.currentThread().getContextClassLoader()
Thread.currentThread().setContextClassLoader(SMTPMailServer.class.classLoader)
mailServer.send(email)
Thread.currentThread().setContextClassLoader(threadClassLoader)

After running the script above and successfully sent an email, using back the old script seems to be working fine up until Jira is restarted.

Basically, the steps are:

1. Send an email for the first time - Error
2. Add the thread code - Worked
3. Removed the thread code - Worked
4. Restart Jira - Error again
5. Then back to step 2

Additional Info

• Jira 8.9.1 - Working fine.
• Jira 8.10.0 & 8.13.2 - Error.