diff --git a/groovy-mail/src/main/java/org/xbib/groovy/smtp/SMTP.java b/groovy-mail/src/main/java/org/xbib/groovy/smtp/SMTP.java
index 03909af..863914b 100644
--- a/groovy-mail/src/main/java/org/xbib/groovy/smtp/SMTP.java
+++ b/groovy-mail/src/main/java/org/xbib/groovy/smtp/SMTP.java
@@ -1,5 +1,6 @@
 package org.xbib.groovy.smtp;
 
+import java.util.List;
 import javax.mail.Address;
 import javax.mail.Authenticator;
 import javax.mail.Message;
@@ -27,22 +28,25 @@ public class SMTP {
 
     private final String password;
 
-    private SMTP(String url, String username, String password) {
+    private final boolean debug;
+
+    private SMTP(String url, String username, String password, boolean debug) {
         this.url = url;
         this.username = username;
         this.password = password;
+        this.debug = debug;
     }
 
     public static SMTP newInstance() {
-        return new SMTP(DEFAULT_URL, null, null);
+        return new SMTP(DEFAULT_URL, null, null, false);
     }
 
     public static SMTP newInstance(String url) {
-        return new SMTP(url, null, null);
+        return new SMTP(url, null, null, false);
     }
 
-    public static SMTP newInstance(String url, String username, String password) {
-        return new SMTP(url, username, password);
+    public static SMTP newInstance(String url, String username, String password, boolean debug) {
+        return new SMTP(url, username, password, debug);
     }
 
     public String getURL() {
@@ -50,17 +54,77 @@ public class SMTP {
     }
 
     public void send(String subject, String from, String to, String text) throws Exception {
-        Address[] toAddr = { new InternetAddress(to) };
+        if (from == null) {
+            return;
+        }
+        if (to == null) {
+            return;
+        }
+        String[] s = to.split(",");
+        Address[] toAddr = new Address[s.length];
+        for (int i = 0; i < s.length; i++) {
+            toAddr[i] = new InternetAddress(s[i]);
+        }
         send(subject, new InternetAddress(from), null, toAddr, null, null, text);
     }
 
+    public void send(String subject, String from, List<String> to, String text) throws Exception {
+        if (from == null) {
+            return;
+        }
+        if (to == null) {
+            return;
+        }
+        if (to.size() > 0) {
+            Address[] toAddr = new Address[to.size()];
+            for (int i = 0; i < to.size(); i++) {
+                toAddr[i] = new InternetAddress(to.get(i));
+            }
+            send(subject, new InternetAddress(from), null, toAddr, null, null, text);
+        }
+    }
+
+    public void send(String subject, String from, List<String> to, List<String> cc, List<String> bcc, String text) throws Exception {
+        if (from == null) {
+            return;
+        }
+        if (to == null) {
+            return;
+        }
+        Address[] toAddr = null;
+        if (to.size() > 0) {
+            toAddr = new Address[to.size()];
+            for (int i = 0; i < to.size(); i++) {
+                toAddr[i] = new InternetAddress(to.get(i));
+            }
+        }
+        Address[] ccAddr = null;
+        if (cc != null && cc.size() > 0) {
+            ccAddr = new Address[cc.size()];
+            for (int i = 0; i < cc.size(); i++) {
+                ccAddr[i] = new InternetAddress(cc.get(i));
+            }
+        }
+        Address[] bccAddr = null;
+        if (bcc != null && bcc.size() > 0) {
+            bccAddr = new Address[bcc.size()];
+            for (int i = 0; i < bcc.size(); i++) {
+                bccAddr[i] = new InternetAddress(bcc.get(i));
+            }
+        }
+        send(subject, new InternetAddress(from), null, toAddr, ccAddr, bccAddr, text);
+    }
+
     public void send(String subject, Address from, Address[] to, String text) throws Exception {
         send(subject, from, null, to, null, null, text);
     }
 
     public void send(String subject,
-                     Address from, Address[] replyTo,
-                     Address[] to, Address[] cc, Address[] bcc,
+                     Address from,
+                     Address[] replyTo,
+                     Address[] to,
+                     Address[] cc,
+                     Address[] bcc,
                      String text) throws Exception {
         Multipart multipart = new MimeMultipart("mixed");
         MimeBodyPart mimeBodyPart = new MimeBodyPart();
@@ -71,8 +135,11 @@ public class SMTP {
     }
 
     public void send(String subject,
-                     Address from, Address[] replyTo,
-                     Address[] to, Address[] cc, Address[] bcc,
+                     Address from,
+                     Address[] replyTo,
+                     Address[] to,
+                     Address[] cc,
+                     Address[] bcc,
                      Multipart multipart) throws Exception {
         WithContext<Object> action = ctx -> {
             Message message = new MimeMessage(ctx.session);
@@ -101,7 +168,7 @@ public class SMTP {
         try {
             if (url != null) {
                 ctx = new SmtpContext();
-                ctx.properties = createEnvironment(url);
+                ctx.properties = createEnvironment(url, debug);
                 ctx.session = username != null ?
                         Session.getDefaultInstance(ctx.properties, new SMTPAuthenticator()) :
                         Session.getDefaultInstance(ctx.properties);
@@ -116,7 +183,7 @@ public class SMTP {
         }
     }
 
-    private static Properties createEnvironment(String urlSpec) {
+    private static Properties createEnvironment(String urlSpec, boolean debug) {
         URI uri = URI.create(urlSpec);
         Properties env = new Properties();
         env.setProperty("mail.smtp.auth",  "false");
@@ -124,7 +191,7 @@ public class SMTP {
         env.setProperty("mail.smtp.port", Integer.toString(uri.getPort()));
         boolean secure = uri.getScheme().equals("smtps") || 995 == uri.getPort();
         env.setProperty("mail.smtp.ssl.enable", secure ? "true" : "false");
-        env.setProperty("mail.debug",  "true");
+        env.setProperty("mail.debug", Boolean.toString(debug));
         return env;
     }