Please someone fix the bug [closed]

I have a Android file whose code is follwed..I had problems with Spinners...

public class first extends Activity  {
 
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);
 
 
         Spinner spincity;
         String[] citynames={"select","Ahmedabad","Vadodara","Surat","Gandhinagar","Himatnagar",
                 "Surendranagar","Navsari","Valsad","Viramgham"};
         spincity=(Spinner) findViewById(R.id.spincity);
         ArrayAdapter<String> a=new ArrayAdapter<String>(this.getApplicationContext(), android.R.layout.simple_spinner_item,citynames);
         a.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
         spincity.setAdapter(a);
 
         spinner.setOnItemSelectedListener(new OnItemSelectedListener() {
 
             @Override
             public void onItemSelected(AdapterView<?> arg0, View arg1,
                     int arg2, long arg3) {
                 // TODO Auto-generated method stub
 
             }
 
             @Override
             public void onNothingSelected(AdapterView<?> arg0) {
                 // TODO Auto-generated method stub
 
             }
         });
     }
 }
 

The layout file .xml is as below:

<?xml version="1.0" encoding="utf-8"?>
 <ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/ScrollView01"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent" >
 
     <RelativeLayout
         android:id="@+id/RelativeLayout01"
         android:layout_width="fill_parent"
         android:layout_height="fill_parent" >
 
         <LinearLayout
                     android:orientation="horizontal"
                     android:layout_width="wrap_content"
                     android:layout_height="wrap_content">
                     <TextView
                         android:id="@+id/city"
                         android:text="City :"
                         android:layout_width="100dp"
                         android:layout_height="wrap_content"
                         android:gravity="left"
                         />
                     <Spinner
                         android:id="@+id/spincity"  
                         android:layout_width="220dp"
                         android:layout_height="wrap_content">
                     </Spinner>
                 </LinearLayout>
         </RelativeLayout>
         </ScrollView>
 

This code gives a NullPointerException. I have tried my best but couldn't resolve it.
The Logcat is as follow::

02-23 16:04:19.554: ERROR/AndroidRuntime(1154): FATAL EXCEPTION: main
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.spinners.changeimage/com.spinners.changeimage.first}: java.lang.NullPointerException
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1569)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at android.os.Handler.dispatchMessage(Handler.java:99)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at android.os.Looper.loop(Looper.java:123)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at android.app.ActivityThread.main(ActivityThread.java:3683)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at java.lang.reflect.Method.invokeNative(Native Method)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at java.lang.reflect.Method.invoke(Method.java:507)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at dalvik.system.NativeStart.main(Native Method)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154): Caused by: java.lang.NullPointerException
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at android.content.ContextWrapper.getResources(ContextWrapper.java:80)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at com.spinners.changeimage.first.<init>(first.java:17)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at java.lang.Class.newInstanceImpl(Native Method)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at java.lang.Class.newInstance(Class.java:1409)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1561)
 02-23 16:04:19.554: ERROR/AndroidRuntime(1154):     ... 11 more
 

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