ArrayList<Class> wird nicht auf Null gesetzt

public class CustomAdapter extends ArrayAdapter<Kapitel>{
   
    // Declare Variables
    Context context;
    LayoutInflater inflater;
    private ArrayList<Kapitel> hisnulmuslim_kapitel_this = null;
    private ArrayList<Kapitel> arraylist = null;
   
    public CustomAdapter(Context context, int textViewResourceId, ArrayList<Kapitel> hisnulmuslim_kapitel) {
        super(context, textViewResourceId, hisnulmuslim_kapitel);

        hisnulmuslim_kapitel_this = hisnulmuslim_kapitel;
        this.context = context;

        inflater = LayoutInflater.from(context);
 
        this.arraylist = new ArrayList<Kapitel>();
        this.arraylist.addAll(hisnulmuslim_kapitel);
    }
 
    public static class ViewHolder{
        TextView titel;
    }
 
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View v = convertView;
        ViewHolder holder;
        if (v == null) {
            //LayoutInflater vi = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            v = inflater.inflate(R.layout.list_item, null);           

            // text view label
            TextView tv_titel = (TextView) v.findViewById(R.id.list_item_titel);
           
            holder = new ViewHolder();
            holder.titel = tv_titel;
            v.setTag(holder);
        }
        else
            holder=(ViewHolder)v.getTag();
 
        final Kapitel custom = hisnulmuslim_kapitel_this.get(position);
       
        if (custom != null) {
            holder.titel.setText(custom.getTitel());
        }
       
        return v;
    }
}

public class Fragment1 extends Fragment {

    DatabaseAdapter dbHelper;

    ListView listView;
    private CustomAdapter adapter;
    ArrayList<Kapitel> hisnulmuslim_kapitel;
   
    ListView listView2;
    private CustomAdapter adapter2;
    ArrayList<Kapitel> hisnulmuslim_kapitel2;
   
    ListView listView3;
    private CustomAdapter adapter3;
    ArrayList<Kapitel> hisnulmuslim_kapitel3;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View rootView = inflater.inflate(R.layout.fragment_1, container, false);

        dbHelper = new DatabaseAdapter(getActivity());
        dbHelper.open();

            // ListView 1
            hisnulmuslim_kapitel = dbHelper.getBittgebeteNachUnterkategorie(1);
           
            listView = (ListView) rootView.findViewById(R.id.listview_1);
   
            adapter = new CustomAdapter(getActivity(),
                    R.id.listview_1,
                    hisnulmuslim_kapitel);

            listView.setAdapter(adapter);
            adapter.notifyDataSetChanged();
            setListViewHeightBasedOnChildren(listView);


            // ListView 2
            hisnulmuslim_kapitel2 = dbHelper.getBittgebeteNachUnterkategorie(2);
           
            listView2 = (ListView) rootView.findViewById(R.id.listview_2);
   
            adapter2 = new CustomAdapter(getActivity(),
                    R.id.listview_2,
                    hisnulmuslim_kapitel2);

            listView2.setAdapter(adapter2);
            adapter2.notifyDataSetChanged();
            setListViewHeightBasedOnChildren(listView2);


            // ListView 2
            hisnulmuslim_kapitel3 = dbHelper.getBittgebeteNachUnterkategorie(3);
           
            listView3 = (ListView) rootView.findViewById(R.id.listview_3);
   
            adapter3 = new CustomAdapter(getActivity(),
                    R.id.listview_3,
                    hisnulmuslim_kapitel3);

            listView3.setAdapter(adapter3);
            adapter3.notifyDataSetChanged();
            setListViewHeightBasedOnChildren(listView3);
       
        dbHelper.close();

        return rootView;
    }
   
    public static void setListViewHeightBasedOnChildren(ListView listView) {
        ListAdapter listAdapter = listView.getAdapter();
        if (listAdapter == null) {
            // pre-condition
            return;
        }

        int totalHeight = 0;
        for (int i = 0; i < listAdapter.getCount(); i++) {
            View listItem = listAdapter.getView(i, null, listView);
            listItem.measure(0, 0);
            totalHeight += listItem.getMeasuredHeight();
        }

        ViewGroup.LayoutParams params = listView.getLayoutParams();
        params.height = totalHeight + (listView.getDividerHeight() * (listAdapter.getCount() - 1));
        listView.setLayoutParams(params);
    }
}

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:fillViewport="true" >

    <LinearLayout
        android:id="@+id/ll_fragment"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:background="@color/farbe_1" >
       
        <LinearLayout
            android:id="@+id/ll_fragment_1"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">
           
            <TextView
                android:id="@+id/headline_1"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="5dp"
                android:padding="10dp"
                android:text="@string/unterkat_1"
                android:textColor="@color/white"
                android:textStyle="bold"
                android:textSize="15sp"
                android:fontFamily="sans-serif-medium" />
           
            <ListView
                android:id="@+id/listview_1"
                android:background="@color/list_bg"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="5dp"
                android:layout_marginTop="5dp" />
               
        </LinearLayout>
       
        <LinearLayout
            android:id="@+id/ll_fragment_2"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">
           
            <TextView
                android:id="@+id/headline_2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="5dp"
                android:padding="10dp"
                android:text="@string/unterkat_2"
                android:textColor="@color/white"
                android:textStyle="bold"
                android:textSize="15sp"
                android:fontFamily="sans-serif-medium" />   
           
            <ListView
                android:id="@+id/listview_2"
                android:background="@color/list_bg"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="5dp"
                android:layout_marginTop="5dp" />
               
        </LinearLayout>
       
        <LinearLayout
            android:id="@+id/ll_fragment_3"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">
       
            <TextView
                android:id="@+id/headline_3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="5dp"
                android:padding="10dp"
                android:text="@string/unterkat_3"
                android:textColor="@color/white"
                android:textStyle="bold"
                android:textSize="15sp"
                android:fontFamily="sans-serif-medium" />
           
            <ListView
                android:id="@+id/listview_3"
                android:background="@color/list_bg"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="5dp"
                android:layout_marginTop="5dp" />
               
        </LinearLayout>

    </LinearLayout>
</ScrollView>

public ArrayList<Kapitel> getBittgebeteNachUnterkategorie(int unterkategorie_id) {
        
        cursor = db.query(    DBHelper.TABLE_NAME_KAPITELN,
                            new String[] { DBHelper.ID_COLUMN , DBHelper.TITEL_COLUMN },
                            DBHelper.UNTERKATEGORIE_COLUMN + "=?",
                            new String[] { String.valueOf(unterkategorie_id) },
                            null, null, null, null);
        
        cursor.moveToFirst();
        do {
            kapitel = new Kapitel();
            
            int id = cursor.getInt(0);
            String titel = cursor.getString(1);

            kapitel.setId(id);
            kapitel.setTitel(titel);
            
            hisnulmuslim_kapitel.add(kapitel);
        } while (cursor.moveToNext());
        
        return hisnulmuslim_kapitel;
    }

do {
            kapitel = new Kapitel();
             
[B]             [I]hisnulmuslim_kapitel = new ArrayList<Kapitel>();[/I][/B]

            int id = cursor.getInt(0);
            String titel = cursor.getString(1);
            kapitel.setId(id);
            kapitel.setTitel(titel);

            hisnulmuslim_kapitel.add(kapitel);
} while (cursor.moveToNext());

public ArrayList<Kapitel> getBittgebeteNachUnterkategorie(int unterkategorie_id) {
        
        cursor = db.query(    DBHelper.TABLE_NAME_KAPITELN,
                            new String[] { DBHelper.ID_COLUMN , DBHelper.TITEL_COLUMN },
                            DBHelper.UNTERKATEGORIE_COLUMN + "=?",
                            new String[] { String.valueOf(unterkategorie_id) },
                            null, null, null, null);


        while (cursor.moveToNext()) {
            kapitel = new Kapitel();

            hisnulmuslim_kapitel = new ArrayList<Kapitel>();

            int id = cursor.getInt(0);
            String titel = cursor.getString(1);

            kapitel.setId(id);
            kapitel.setTitel(titel);
            
            hisnulmuslim_kapitel.add(kapitel);
        }
        
        return hisnulmuslim_kapitel;
}

kapitel = new Kapitel();

        hisnulmuslim_kapitel = new ArrayList<Kapitel>();
        
        while (cursor.moveToNext()) {
            int id = cursor.getInt(0);
            String titel = cursor.getString(1);

            kapitel.setId(id);
            kapitel.setTitel(titel);
            
            hisnulmuslim_kapitel.add(kapitel);
}