diff --git a/helpmehelpapplication/src/main/java/ntnu/sytemutvikling/team6/models/Inbox.java b/helpmehelpapplication/src/main/java/ntnu/sytemutvikling/team6/models/Inbox.java
index 37b7013..17f495d 100644
--- a/helpmehelpapplication/src/main/java/ntnu/sytemutvikling/team6/models/Inbox.java
+++ b/helpmehelpapplication/src/main/java/ntnu/sytemutvikling/team6/models/Inbox.java
@@ -6,7 +6,7 @@
 // Enhetstester mangler
 
 /**
- * Represents a users inbox that contains messages.
+ * Represents a user's inbox that contains messages.
  * Provides methods to add, remove and get messages.
  *
  * @author  Robin Strand Prestmo
@@ -24,7 +24,7 @@ public Inbox() {
   /**
    * Returns an unmodifiable view of the messages in this inbox.
    *
-   * @return an unmodifiable list of messages.
+   * @return an unmodifiable list of messages
    */
   public List<Message> getMessages() {
     return Collections.unmodifiableList(messages);
@@ -33,8 +33,9 @@ public List<Message> getMessages() {
   /**
    * Finds a specific message by id.
    *
-   * @param messageId is the ID to the message that is searching after.
-   * @return message with matching id if the id exists.
+   * @param messageId the id of the message to search for
+   * @return messageId the id of the message to remove
+   * @throws IllegalArgumentException if messageId is null
    */
   public Optional<Message> findMessageById(UUID messageId) {
     if (messageId == null) {
@@ -47,8 +48,12 @@ public Optional<Message> findMessageById(UUID messageId) {
    * Add´s message to the messages list.
    *
    * @param message to be added
+   * @throws IllegalArgumentException if message is null
    */
   public void addMessage(Message message) {
+    if (message == null) {
+      throw new IllegalArgumentException("Message cannot be null");
+    }
     messages.add(message);
   }
 
@@ -56,9 +61,13 @@ public void addMessage(Message message) {
    * Removes a message from the inbox list.
    *
    * @param messageId the id to the message to be removed
-   * @return true if the message was removed, false if not found.
+   * @return true if the message was removed, false if not found
+   * @throws IllegalArgumentException if messageId is null
    */
   public boolean removeMessage(UUID messageId) {
+    if (messageId == null) {
+      throw new IllegalArgumentException("MessageId cannot be null");
+    }
     return messages.removeIf(message -> messageId.equals(message.getId()));
   }
 }