NullPointer exception while reading epub file from assets in android

I am accesing epub file from assets folder to read the epub content.I followed siegmann step by step. It is throwing nulpointer exception at ``` Book book = (new EpubReader()).readEpub(epubInputStream); ``` My code snippet is ``` public class MainActivity extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); AssetManager assetManager = getAssets(); System.err.println("assetManager>>"+assetManager); try { // find InputStream for book InputStream epubInputStream = assetManager.open("ww.epub"); // Load Book from inputStream Book book = (new EpubReader()).readEpub(epubInputStream); // Log the book's authors Log.i("epublib", "author(s): " + book.getMetadata().getAuthors()); // Log the book's title Log.i("epublib", "title: " + book.getTitle()); // Log the book's coverimage property Bitmap coverImage = BitmapFactory.decodeStream(book.getCoverImage().getInputStream()); Log.i("epublib", "Coverimage is " + coverImage.getWidth() + " by " + coverImage.getHeight() + " pixels"); // Log the tale of contents logTableOfContents(book.getTableOfContents().getTocReferences(), 0); } catch (IOException e) { Log.e("epublib", e.getMessage()); } } private void logTableOfContents(List<TOCReference> tocReferences, int depth) { if (tocReferences == null) { return; } for (TOCReference tocReference : tocReferences) { StringBuilder tocString = new StringBuilder(); for (int i = 0; i < depth; i++) { tocString.append("\t"); } tocString.append(tocReference.getTitle()); Log.i("epublib", tocString.toString()); logTableOfContents(tocReference.getChildren(), depth + 1); } } } ``` `ww.epub` is the file i kept simply in assets folder.Could anyone tell me how can i solve this nullpointer exception? Logcat shows ``` 02-04 13:22:57.189: W/System.err(22968): 1915 [main] ERROR nl.siegmann.epublib.epub.NCXDocument - null 02-04 13:22:57.189: W/System.err(22968): java.lang.NullPointerException 02-04 13:22:57.189: W/System.err(22968): at nl.siegmann.epublib.epub.NCXDocument.read(NCXDocument.java:92) 02-04 13:22:57.189: W/System.err(22968): at nl.siegmann.epublib.epub.EpubReader.processNcxResource(EpubReader.java:113) 02-04 13:22:57.189: W/System.err(22968): at nl.siegmann.epublib.epub.EpubReader.readEpub(EpubReader.java:99) 02-04 13:22:57.189: W/System.err(22968): at nl.siegmann.epublib.epub.EpubReader.readEpub(EpubReader.java:53) 02-04 13:22:57.189: W/System.err(22968): at nl.siegmann.epublib.epub.EpubReader.readEpub(EpubReader.java:37) 02-04 13:22:57.189: W/System.err(22968): at com.example.epub.MainActivity.onCreate(MainActivity.java:36) 02-04 13:22:57.189: W/System.err(22968): at android.app.Activity.performCreate(Activity.java:5104) 02-04 13:22:57.189: W/System.err(22968): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 02-04 13:22:57.189: W/System.err(22968): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 02-04 13:22:57.189: W/System.err(22968): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 02-04 13:22:57.189: W/System.err(22968): at android.app.ActivityThread.access$600(ActivityThread.java:141) 02-04 13:22:57.189: W/System.err(22968): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 02-04 13:22:57.189: W/System.err(22968): at android.os.Handler.dispatchMessage(Handler.java:99) 02-04 13:22:57.189: W/System.err(22968): at android.os.Looper.loop(Looper.java:137) 02-04 13:22:57.189: W/System.err(22968): at android.app.ActivityThread.main(ActivityThread.java:5039) 02-04 13:22:57.189: W/System.err(22968): at java.lang.reflect.Method.invokeNative(Native Method) 02-04 13:22:57.189: W/System.err(22968): at java.lang.reflect.Method.invoke(Method.java:511) 02-04 13:22:57.189: W/System.err(22968): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 02-04 13:22:57.189: W/System.err(22968): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 02-04 13:22:57.189: W/System.err(22968): at dalvik.system.NativeStart.main(Native Method) 02-04 13:22:57.189: I/epublib(22968): author(s): [Melville, Herman] 02-04 13:22:57.189: I/epublib(22968): title: Moby-Dick 02-04 13:22:57.189: D/AndroidRuntime(22968): Shutting down VM 02-04 13:22:57.189: W/dalvikvm(22968): threadid=1: thread exiting with uncaught exception (group=0x41e99930) 02-04 13:22:57.189: E/AndroidRuntime(22968): FATAL EXCEPTION: main 02-04 13:22:57.189: E/AndroidRuntime(22968): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.epub/com.example.epub.MainActivity}: java.lang.NullPointerException 02-04 13:22:57.189: E/AndroidRuntime(22968): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 02-04 13:22:57.189: E/AndroidRuntime(22968): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 02-04 13:22:57.189: E/AndroidRuntime(22968): at android.app.ActivityThread.access$600(ActivityThread.java:141) 02-04 13:22:57.189: E/AndroidRuntime(22968): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 02-04 13:22:57.189: E/AndroidRuntime(22968): at android.os.Handler.dispatchMessage(Handler.java:99) 02-04 13:22:57.189: E/AndroidRuntime(22968): at android.os.Looper.loop(Looper.java:137) 02-04 13:22:57.189: E/AndroidRuntime(22968): at android.app.ActivityThread.main(ActivityThread.java:5039) 02-04 13:22:57.189: E/AndroidRuntime(22968): at java.lang.reflect.Method.invokeNative(Native Method) 02-04 13:22:57.189: E/AndroidRuntime(22968): at java.lang.reflect.Method.invoke(Method.java:511) 02-04 13:22:57.189: E/AndroidRuntime(22968): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 02-04 13:22:57.189: E/AndroidRuntime(22968): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 02-04 13:22:57.189: E/AndroidRuntime(22968): at dalvik.system.NativeStart.main(Native Method) 02-04 13:22:57.189: E/AndroidRuntime(22968): Caused by: java.lang.NullPointerException 02-04 13:22:57.189: E/AndroidRuntime(22968): at com.example.epub.MainActivity.onCreate(MainActivity.java:45) 02-04 13:22:57.189: E/AndroidRuntime(22968): at android.app.Activity.performCreate(Activity.java:5104) 02-04 13:22:57.189: E/AndroidRuntime(22968): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 02-04 13:22:57.189: E/AndroidRuntime(22968): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 02-04 13:22:57.189: E/AndroidRuntime(22968): ... 11 more ```