Wen es interessiert hier der lauffähige Code.
Bin aber bereits am Probieren, das mit dem AppServer zu machen.

Code:
     H main(Main)
     H dftactgrp(*no)
     H actgrp(*new)

      **********************************************************************
      *  newString constructor that accepts a byte array
      *  (an alphnumeric variable in RPG speak). It
      *  returns a string object.
      **********************************************************************
     D newString       PR              O   ExtProc(*JAVA:
     D                                             'java.lang.String':
     D                                             *CONSTRUCTOR)
     D                                     Class(*JAVA:'java.lang.String')
     D  byes                       9999A   Const Varying


     D  sendMail       PR                  EXTPROC(*JAVA : 'javaMail.JavaMail+
     D                                     ' : 'sendMail' )
     D                                     STATIC
     D  arg0                           O   CLASS(*JAVA : 'java.lang.String' )
     D  arg1                           O   CLASS(*JAVA : 'java.lang.String' )
     D  arg2                           O   CLASS(*JAVA : 'java.lang.String' )
     D  arg3                           O   CLASS(*JAVA : 'java.lang.String' )

     D sendMailMitAnhang...
     D                 PR                  EXTPROC(*JAVA : 'javaMail.JavaMail+
     D                                     ' : 'sendMailMitAnhang' )
     D                                     STATIC
     D  arg0                           O   CLASS(*JAVA : 'java.lang.String' )
     D  arg1                           O   CLASS(*JAVA : 'java.lang.String' )
     D  arg2                           O   CLASS(*JAVA : 'java.lang.String' )
     D  arg3                           O   CLASS(*JAVA : 'java.lang.String' )
     D  arg4                           O   DIM(99)
     D                                     CLASS(*JAVA : 'java.lang.String' )
     D                                     OPTIONS(*VARSIZE)

     D  absender       S               O   CLASS(*JAVA : 'java.lang.String' )
     D  empfaenger     S               O   CLASS(*JAVA : 'java.lang.String' )
     D  betreff        S               O   CLASS(*JAVA : 'java.lang.String' )
     D  nachricht      S               O   CLASS(*JAVA : 'java.lang.String' )
     D  dateien        S               O   DIM(99)
     D                                     CLASS(*JAVA : 'java.lang.String' )

     DMain             PR                  extpgm('TEST')

     PMain             B
     D                 PI
      /free

       absender = newString('absender@test.local');
       empfaenger = newString('empfaenger@test.local');
       betreff = newString('Test');
       nachricht = newString('Datei-Test');
       dateien(1) = newString('/Java/JavaMail.jar');
       dateien(2) = newString('/Java/activation.jar');
       dateien(3) = newString('/Java/mail.jar');
       sendMail(absender:empfaenger:betreff:nachricht);
       sendMailMitAnhang(
         absender:empfaenger:betreff:nachricht:dateien);
       dsply ('Ende');
      /end-free
     P                 E
Code:
package javaMail;

import java.io.File;
import java.util.Properties;

import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.activation.FileDataSource;
import javax.mail.BodyPart;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;

public class JavaMail {

	public static void main(String[] args) {
		String absender = args[0];
		String empfaenger = args[1];
		String betreff = args[2];
		String nachricht = args[3];
		String[] dateien = new String[1];
		dateien[0] = args[4];
		sendMail(absender, empfaenger, betreff, nachricht);
		sendMailMitAnhang(
			absender, empfaenger, betreff, 
			nachricht, dateien);
	}
	
	public static void sendMailMitAnhang(
		String absender, String empfaenger, String betreff, 
		String nachricht, String[] dateien)
	{
		File[] files = new File[dateien.length];
		for (int i=0; i<dateien.length; i++)
		{
			if (dateien[i]!=null)
			{
				files[i] = new File(dateien[i]);
			}
		}
		try {
			Properties props=new Properties();
			props.put("mail.smtp.host","IP-Adresse Mail Server");
			Session session = Session.getInstance(props);
			Message message=new MimeMessage(session);
			message.setFrom(new InternetAddress(absender));
			message.setRecipient(
				Message.RecipientType.TO, 
				new InternetAddress(empfaenger));
			message.setSubject(betreff);
			Multipart multipart = new MimeMultipart();
			BodyPart body = new MimeBodyPart();
			body.setText(nachricht);
			multipart.addBodyPart(body);
			for (int i=0; i<files.length; i++)
			{
				if (files[i]!=null)
				{
					BodyPart file = new MimeBodyPart();
					DataSource source = new FileDataSource(files[i]);
					file.setDataHandler(new DataHandler(source));
					file.setFileName(files[i].getName());
					multipart.addBodyPart(file);
				}
			}
			message.setContent(multipart);
			Transport.send(message);
		} catch (AddressException e) {
			e.printStackTrace();
		} catch (MessagingException e) {
			e.printStackTrace();
		}
		
	}

	public static void sendMail(
		String absender, String empfaenger, 
		String betreff, String nachricht)
	{
		try {
			Properties props=new Properties();
			props.put("mail.smtp.host","IP-Adresse Mail Server");
			Session session = Session.getInstance(props);
			Message message=new MimeMessage(session);
			message.setFrom(new InternetAddress(absender));
			message.setRecipient(
				Message.RecipientType.TO, 
				new InternetAddress(empfaenger));
			message.setSubject(betreff);
			Multipart multipart = new MimeMultipart();
			BodyPart body = new MimeBodyPart();
			body.setText(nachricht);
			multipart.addBodyPart(body);
			message.setContent(multipart);
			Transport.send(message);
		} catch (AddressException e) {
			e.printStackTrace();
		} catch (MessagingException e) {
			e.printStackTrace();
		}
	}
}