At the time of start new activity, my android app shows NullPointerException and unfortunately stopped. how to fix

public class FirstActivity extends Activity {
	TextView welcomeText;
    Button goToWishListButton;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_first);

        welcomeText= (TextView) findViewById(R.id.welcomeText);
        goToWishListButton = (Button) findViewById(R.id.goToWishButton);

        goToWishListButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(FirstActivity.this, WishListActivity.class);
                startActivity(intent);

            }
        });

public class WishListActivity extends Activity {

    EditText inputText;
    Button addWishButton;
    ListView wishListView;
    ArrayList<item> arrayList;
    BaseAdapter adapter;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_wish_list);
        initializeAll();
        arrayList = new ArrayList<item>();
	}
    private  void initializeAll()
    {
        inputText = (EditText) findViewById(R.id.wishNameEdit);
        addWishButton = (Button) findViewById(R.id.saveWishButton);
        wishListView = (ListView) findViewById(R.id.listView);
        adapter = new BaseAdapter() {
            LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);

            @Override
            public View getView(int position, View view, ViewGroup viewGroup) {
                if (view==null)
                {
                    view= inflater.inflate(R.layout.wish_list, null);
                }

                TextView wishTextView = (TextView) view.findViewById(R.id.wishTextView);
                TextView wishDateView = (TextView) view.findViewById(R.id.wishDateView);

                wishTextView.setText(arrayList.get(position).getWishString());
                Date date = arrayList.get(position).getDate();
                wishDateView.setText(DateFormat.format("dd/MM/yyyy HH/mm/ss a", date));

                return view;
            }


            @Override
            public long getItemId(int position) {
                return 0;
            }

            @Override
            public int getCount() {
                return arrayList.size();
            }

            @Override
            public Object getItem(int position) {
                return arrayList.get(position);
            }


        };

        wishListView.setAdapter(adapter);

<manifest xmlns:android="http://schemas.android.com/apk/res/android">
    package="com.misbah.wishlistapp"
    android:versionCode="1"
    android:versionName="1.0" &gt;

    <uses-sdk>
        android:minSdkVersion="16"
        android:targetSdkVersion="19" /&gt;

    <application>
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" &gt;

        <activity>
            android:name=".FirstActivity"
            android:label="@string/app_name" &gt;

            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" /&gt;
            </intent-filter>
        </activity>
    </application>
</uses-sdk></manifest></item></item>