Sending Java Mail from EAP 8.0.x results in a "RuntimeException: Provider for jakarta.activation.spi.MailcapRegistryProvider cannot be found"

Issue

• To use Java Mail functionality in JBoss EAP 8.0.x, updated the package from javax. to jakarta. namespace and added two required JARs for Jakarta Mail, jakarta.mail-api-xxx.jar and jakarta.activation-api-xxx.jar to the classpath, but following error still occurs:

  java.lang.RuntimeException: Provider for jakarta.activation.spi.MailcapRegistryProvider cannot be found
     at jakarta.activation.FactoryFinder.find(FactoryFinder.java:95)
     at jakarta.activation.MailcapCommandMap.getImplementation(MailcapCommandMap.java:705)
     at jakarta.activation.MailcapCommandMap.loadFile(MailcapCommandMap.java:284)
     at jakarta.activation.MailcapCommandMap.<init>(MailcapCommandMap.java:154)
     at jakarta.activation.CommandMap.getDefaultCommandMap(CommandMap.java:60)
     at jakarta.activation.DataHandler.getCommandMap(DataHandler.java:128)
     at jakarta.activation.DataHandler.getDataContentHandler(DataHandler.java:590)
     at jakarta.activation.DataHandler.writeTo(DataHandler.java:290)
     at jakarta.mail.internet.MimeUtility.getEncoding(MimeUtility.java:318)
     at jakarta.mail.internet.MimeBodyPart.updateHeaders(MimeBodyPart.java:1562)
     at jakarta.mail.internet.MimeBodyPart.updateHeaders(MimeBodyPart.java:1156)
     at jakarta.mail.internet.MimeMultipart.updateHeaders(MimeMultipart.java:509)
     at jakarta.mail.internet.MimeBodyPart.updateHeaders(MimeBodyPart.java:1520)
     at jakarta.mail.internet.MimeMessage.updateHeaders(MimeMessage.java:2270)
     at jakarta.mail.internet.MimeMessage.saveChanges(MimeMessage.java:2230)
     at jakarta.mail.Transport.send(Transport.java:101)
  

• This occurs within a standalone Java application project in the IDE development environment, used for testing before deployment to the JBoss EAP 8 server.