diff --git a/smack-extensions/src/main/java/org/jivesoftware/smackx/address/MultipleRecipientManager.java b/smack-extensions/src/main/java/org/jivesoftware/smackx/address/MultipleRecipientManager.java
index a2c73552a..630d37c8b 100644
--- a/smack-extensions/src/main/java/org/jivesoftware/smackx/address/MultipleRecipientManager.java
+++ b/smack-extensions/src/main/java/org/jivesoftware/smackx/address/MultipleRecipientManager.java
@@ -19,6 +19,7 @@ package org.jivesoftware.smackx.address;
 
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.List;
 
 import org.jivesoftware.smack.SmackException.FeatureNotSupportedException;
@@ -228,18 +229,16 @@ public class MultipleRecipientManager {
             throw new AssertionError();
         }
 
+        if (to == null) to = Collections.emptyList();
+        if (cc == null) cc = Collections.emptyList();
+        if (bcc == null) bcc = Collections.emptyList();
+
         final int numRecipients = to.size() + cc.size() + bcc.size();
         final List<Jid> recipients = new ArrayList<>(numRecipients);
 
-        if (to != null) {
-            recipients.addAll(to);
-        }
-        if (cc != null) {
-            recipients.addAll(cc);
-        }
-        if (bcc != null) {
-            recipients.addAll(bcc);
-        }
+        recipients.addAll(to);
+        recipients.addAll(cc);
+        recipients.addAll(bcc);
 
         final List<Stanza> stanzasToSend = new ArrayList<>(numRecipients);
         for (Jid recipient : recipients) {
diff --git a/smack-extensions/src/main/java/org/jivesoftware/smackx/xdata/form/FillableForm.java b/smack-extensions/src/main/java/org/jivesoftware/smackx/xdata/form/FillableForm.java
index 9954e8a2e..159c20544 100644
--- a/smack-extensions/src/main/java/org/jivesoftware/smackx/xdata/form/FillableForm.java
+++ b/smack-extensions/src/main/java/org/jivesoftware/smackx/xdata/form/FillableForm.java
@@ -58,7 +58,13 @@ public class FillableForm extends FilledForm {
             if (formField.isRequired()) {
                 String fieldName = formField.getFieldName();
                 requiredFields.add(fieldName);
-                missingRequiredFields.add(fieldName);
+
+                if (formField.hasValueSet()) {
+                    // This is a form field with a default value.
+                    write(formField);
+                } else {
+                    missingRequiredFields.add(fieldName);
+                }
             }
         }
         this.requiredFields = Collections.unmodifiableSet(requiredFields);
@@ -223,9 +229,6 @@ public class FillableForm extends FilledForm {
         if (!getDataForm().hasField(fieldName)) {
             throw new IllegalArgumentException();
         }
-        if (filledFields.containsKey(fieldName)) {
-            throw new IllegalArgumentException();
-        }
 
         // Perform validation, e.g. using XEP-0122.
         // TODO: We could also perform list-* option validation, but this has to take xep122's <open/> into account.