Two Exception

[lsqbeyond]

Hello, I've just met these two mistakes. May I have a problem in the format of my book? But most of my books are, and the problem is a jar. I can't modify it. If I need a book, please send a mailbox lsqbeyond@yeah.net. to solve these two problems. Thanks very much

Shutting down VM
01-03 23:30:32.372 22952-22952/com.folioreader.android.sample E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.folioreader.android.sample, PID: 22952
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.folioreader.android.sample/com.folioreader.ui.folio.activity.FolioActivity}: java.lang.NullPointerException: Attempt to invoke interface method 'java.lang.String org.w3c.dom.Element.getTextContent()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2664)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2733)
at android.app.ActivityThread.access$900(ActivityThread.java:187)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1584)
at android.os.Handler.dispatchMessage(Handler.java:111)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5877)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1019)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:814)
Caused by: java.lang.NullPointerException: Attempt to invoke interface method 'java.lang.String org.w3c.dom.Element.getTextContent()' on a null object reference
at org.readium.r2_streamer.parser.OPFParser.parseMainTitle(OPFParser.java:206)
at org.readium.r2_streamer.parser.OPFParser.parseOpfFile(OPFParser.java:50)
at org.readium.r2_streamer.parser.EpubParser.parseEpubFile(EpubParser.java:47)
at org.readium.r2_streamer.server.EpubServer.parse(EpubServer.java:90)
at org.readium.r2_streamer.server.EpubServer.addEpub(EpubServer.java:40)
at com.folioreader.ui.folio.activity.FolioActivity.addEpub(FolioActivity.java:223)
at com.folioreader.ui.folio.activity.FolioActivity.initBook(FolioActivity.java:211)
at com.folioreader.ui.folio.activity.FolioActivity.setupBook(FolioActivity.java:627)
at com.folioreader.ui.folio.activity.FolioActivity.onCreate(FolioActivity.java:161)
at android.app.Activity.performCreate(Activity.java:6127)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1125)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2617)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2733) 
at android.app.ActivityThread.access$900(ActivityThread.java:187) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1584) 
at android.os.Handler.dispatchMessage(Handler.java:111) 
at android.os.Looper.loop(Looper.java:194) 
at android.app.ActivityThread.main(ActivityThread.java:5877) 
at java.lang.reflect.Method.invoke(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:372) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1019) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:814) 

                                               Process: com.folioreader.android.sample, PID: 24021
                                               java.lang.RuntimeException: Unable to start activity ComponentInfo{com.folioreader.android.sample/com.folioreader.ui.folio.activity.FolioActivity}: java.lang.NullPointerException: Attempt to read from field 'java.util.List org.readium.r2_streamer.model.publication.EpubPublication.links' on a null object reference
                                                   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2664)
                                                   at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2733)
                                                   at android.app.ActivityThread.access$900(ActivityThread.java:187)
                                                   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1584)
                                                   at android.os.Handler.dispatchMessage(Handler.java:111)
                                                   at android.os.Looper.loop(Looper.java:194)
                                                   at android.app.ActivityThread.main(ActivityThread.java:5877)
                                                   at java.lang.reflect.Method.invoke(Native Method)
                                                   at java.lang.reflect.Method.invoke(Method.java:372)
                                                   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1019)
                                                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:814)
                                                Caused by: java.lang.NullPointerException: Attempt to read from field 'java.util.List org.readium.r2_streamer.model.publication.EpubPublication.links' on a null object reference
                                                   at org.readium.r2_streamer.server.EpubServer.addLinks(EpubServer.java:68)
                                                   at org.readium.r2_streamer.server.EpubServer.addEpub(EpubServer.java:42)
                                                   at com.folioreader.ui.folio.activity.FolioActivity.addEpub(FolioActivity.java:223)
                                                   at com.folioreader.ui.folio.activity.FolioActivity.initBook(FolioActivity.java:211)
                                                   at com.folioreader.ui.folio.activity.FolioActivity.setupBook(FolioActivity.java:627)
                                                   at com.folioreader.ui.folio.activity.FolioActivity.onCreate(FolioActivity.java:161)
                                                   at android.app.Activity.performCreate(Activity.java:6127)
                                                   at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1125)
                                                   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2617)
                                                   at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2733) 
                                                   at android.app.ActivityThread.access$900(ActivityThread.java:187) 
                                                   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1584) 
                                                   at android.os.Handler.dispatchMessage(Handler.java:111) 
                                                   at android.os.Looper.loop(Looper.java:194) 
                                                   at android.app.ActivityThread.main(ActivityThread.java:5877) 
                                                   at java.lang.reflect.Method.invoke(Native Method) 
                                                   at java.lang.reflect.Method.invoke(Method.java:372) 
                                                   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1019) 
                                                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:814) 

[mahavir155]

@lsqbeyond please validate your epubs using validator.idpf.org
Meanwhile, we too are making change to fail gracefully in case of invalid epub.

[sumanabhi]

Same issue I am facing. I have already validated the EPUB.
Please resolve this issue ASAP.