java.lang.NullPointerException GoogleMaps V2

i just learning about android programming to show map. but when i run this code ,there's some error. Can anybody explain why this error occurs? And what I can do to fix this problem? thank you very much. Stacktrace: ``` 12-01 02:58:27.324: E/AndroidRuntime(1360): FATAL EXCEPTION: main 12-01 02:58:27.324: E/AndroidRuntime(1360): java.lang.NullPointerException 12-01 02:58:27.324: E/AndroidRuntime(1360): at android.app.Instrumentation.execStartActivity(Instrumentation.java:1417) 12-01 02:58:27.324: E/AndroidRuntime(1360): at android.app.Activity.startActivityForResult(Activity.java:3390) 12-01 02:58:27.324: E/AndroidRuntime(1360): at android.app.Activity.startActivityForResult(Activity.java:3351) 12-01 02:58:27.324: E/AndroidRuntime(1360): at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:839) 12-01 02:58:27.324: E/AndroidRuntime(1360): at android.app.Activity.startActivity(Activity.java:3587) 12-01 02:58:27.324: E/AndroidRuntime(1360): at android.app.Activity.startActivity(Activity.java:3555) 12-01 02:58:27.324: E/AndroidRuntime(1360): at com.google.android.gms.dynamic.a$5.onClick(Unknown Source) 12-01 02:58:27.324: E/AndroidRuntime(1360): at android.view.View.performClick(View.java:4240) 12-01 02:58:27.324: E/AndroidRuntime(1360): at android.view.View$PerformClick.run(View.java:17721) 12-01 02:58:27.324: E/AndroidRuntime(1360): at android.os.Handler.handleCallback(Handler.java:730) 12-01 02:58:27.324: E/AndroidRuntime(1360): at android.os.Handler.dispatchMessage(Handler.java:92) 12-01 02:58:27.324: E/AndroidRuntime(1360): at android.os.Looper.loop(Looper.java:137) 12-01 02:58:27.324: E/AndroidRuntime(1360): at android.app.ActivityThread.main(ActivityThread.java:5103) 12-01 02:58:27.324: E/AndroidRuntime(1360): at java.lang.reflect.Method.invokeNative(Native Method) 12-01 02:58:27.324: E/AndroidRuntime(1360): at java.lang.reflect.Method.invoke(Method.java:525) 12-01 02:58:27.324: E/AndroidRuntime(1360): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737) 12-01 02:58:27.324: E/AndroidRuntime(1360): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 12-01 02:58:27.324: E/AndroidRuntime(1360): at dalvik.system.NativeStart.main(Native Method) 12-01 02:58:29.088: I/Process(1360): Sending signal. PID: 1360 SIG: 9 ``` MainActivity.java ``` package unai.skripsi.mymaps; import com.google.android.gms.maps.CameraUpdateFactory; import com.google.android.gms.maps.GoogleMap; import com.google.android.gms.maps.SupportMapFragment; import com.google.android.gms.maps.model.BitmapDescriptorFactory; import com.google.android.gms.maps.model.LatLng; import com.google.android.gms.maps.model.Marker; import com.google.android.gms.maps.model.MarkerOptions; import android.os.Bundle; import android.support.v4.app.FragmentActivity; import android.view.Menu; public class MainActivity extends FragmentActivity { static final LatLng RAGUNAN = new LatLng(-6.3039, 106.8267); static final LatLng TAMANMINI = new LatLng(-6.29436, 106.8859); private GoogleMap map; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); map= ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap(); if (map!=null){ Marker ragunan = map.addMarker(new MarkerOptions().position(RAGUNAN) .title("Ragunan")); Marker tamanmini = map.addMarker(new MarkerOptions().position(TAMANMINI) .title("Taman mini") .snippet("Taman mini itu indah") .icon(BitmapDescriptorFactory.fromResource(R.drawable.ic_launcher))); map.moveCamera(CameraUpdateFactory.newLatLngZoom(RAGUNAN, 15)); map.animateCamera(CameraUpdateFactory.zoomTo(10), 2000, null); } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } } ``` Layout ``` <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity" > <fragment android:id="@+id/map" android:layout_width="match_parent" android:layout_height="match_parent" android:name="com.google.android.gms.maps.SupportMapFragment" /> </RelativeLayout> ``` Manifest ``` <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="unai.skripsi.mymaps" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="17" /> <permission android:name="unai.skripsi.mymaps.permission.MAPS_RECEIVE" android:protectionLevel="signature" /> <uses-feature android:glEsVersion="0x00020000" android:required="true" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/> <uses-permission android:name="unai.skripsi.mymaps.permission.MAPS_RECEIVE" /> <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" /> <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> <application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name="unai.skripsi.mymaps.MainActivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <meta-data android:name="com.google.android.gms.version" android:value="@integer/google_play_services_version" /> <meta-data android:name="com.google.android.maps.v2.API_KEY" android:value="My API KEY" /> </application> </manifest> ```