I have a ListActivity which has an adapter that crashes. Here is the code that crashes the program:

Question q = new Question ();
q.setQuestion( "" );

questions.add(q);       

adapter = new ArrayAdapter<Question>(this, R.layout.user_question_list, 
        R.id.label,  questions);

Here is how I create the adapter:

ArrayAdapter<Question> adapter; 

ArrayList<Question> questions = new ArrayList <Question>( );        

and the list xml is like this:

<?xml version="1.0" encoding="utf-8"?>

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:padding="10dp"
    android:textSize="16sp" >
</TextView>    

and the overall Activity xml is like this:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" 
    android:orientation="vertical" >    


<TextView
    android:id="@+id/question_label"    
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Loading your questions..."
    />     

    <ListView
    android:id="@android:id/list"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@+id/label"
        android:textSize="20px" >        
    </ListView>

        <Button  
            android:id="@+id/add_question"  
            android:layout_height="wrap_content"  
            android:text="Ask a Question"
            android:onClick="sendFeedback"  
            android:layout_width="fill_parent">  
        </Button>     

</LinearLayout>

Any idea why the code where I try to update the adapter results in the NullPointerException?

Thanks!!