In fact, I want to say, if you use eventBus, then come in and take a look...

Because I recently discovered a bug, which will cause the eventBus to fail to register in the oncreate() method, and the class cannot be found. The problem posted below is actually a very simple solution.
In fact, it is the oncreate rewritten by your activity. method question

如果你重写的时这个方法
 @Override
public void onCreate(Bundle savedInstanceState,
        PersistableBundle persistentState) {
        super.onCreate(savedInstanceState, persistentState);
    }
    那么一定会出现问题,,一直到目前最新的eventbus 3.0也有这个问题
    换成这个就可以了,
     @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

This will solve the problem of the following error,

java.lang.NoClassDefFoundError: 
android/os/PersistableBundle at java.lang.Class.getDeclaredMethods(Native Method)
                                                                       at java.lang.Class.getDeclaredMethods(Class.java:656)
                                                                       at de.greenrobot.event.SubscriberMethodFinder.findSubscriberMethodsWithReflection(SubscriberMethodFinder.java:127)
                                                                       at de.greenrobot.event.SubscriberMethodFinder.findSubscriberMethods(SubscriberMethodFinder.java:79)
                                                                       at de.greenrobot.event.EventBus.register(EventBus.java:135)
                                                                       at com.chinesefluently.activity.MainActivity.onCreate(MainActivity.java:49)
                                                                       at android.app.Activity.performCreate(Activity.java:5231)
                                                                       at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
                                                                       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
                                                                       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
                                                                       at android.app.ActivityThread.access$800(ActivityThread.java:135)
                                                                       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
                                                                       at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                       at android.os.Looper.loop(Looper.java:136)
                                                                       at android.app.ActivityThread.main(ActivityThread.java:5001)
                                                                       at java.lang.reflect.Method.invokeNative(Native Method)
                                                                       at java.lang.reflect.Method.invoke(Method.java:515)
                                                                       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
                                                                       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
                                                                       at dalvik.system.NativeStart.main(Native Method)
                                                                    Caused by: java.lang.ClassNotFoundException: Didn't find class "android.os.PersistableBundle" on path: DexPathList[[zip file "/data/app/com.chinesefluently-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.chinesefluently-1, /system/lib]]
                                                                       at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
                                                                       at java.lang.ClassLoader.loadClass(ClassLoader.java:497)
                                                                       at java.lang.ClassLoader.loadClass(ClassLoader.java:457)
                                                                       at java.lang.Class.getDeclaredMethods(Native Method) 
                                                                       at java.lang.Class.getDeclaredMethods(Class.java:656) 
                                                                       at de.greenrobot.event.SubscriberMethodFinder.findSubscriberMethodsWithReflection(SubscriberMethodFinder.java:127) 
                                                                       at de.greenrobot.event.SubscriberMethodFinder.findSubscriberMethods(SubscriberMethodFinder.java:79) 
                                                                       at de.greenrobot.event.EventBus.register(EventBus.java:135) 
                                                                       at com.chinesefluently.activity.MainActivity.onCreate(MainActivity.java:49) 
                                                                       at android.app.Activity.performCreate(Activity.java:5231) 
                                                                       at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 
                                                                       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148) 
                                                                       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233) 
                                                                       at android.app.ActivityThread.access$800(ActivityThread.java:135) 
                                                                       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) 
                                                                       at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                       at android.os.Looper.loop(Looper.java:136) 
                                                                       at android.app.ActivityThread.main(ActivityThread.java:5001) 
                                                                       at java.lang.reflect.Method.invokeNative(Native Method) 
                                                                       at java.lang.reflect.Method.invoke(Method.java:515) 
                                                                       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785) 
                                                                       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601) 
                                                                       at dalvik.system.NativeStart.main(Native Method)