title: Realm - Realm.init(this) failed in onCreate?
body: <p>I put Realm.init(this) in the onCreate of my Application class.</p>
  
  <p>But it throws an exception while I'm calling Realm.getDefaultInstance() in the onCreate of my Activity.</p>
  
  <pre><code>    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2511)
      at android.app.ActivityThread.-wrap11(ActivityThread.java)
      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1360)
      at android.os.Handler.dispatchMessage(Handler.java:102)
      at android.os.Looper.loop(Looper.java:148)
      at android.app.ActivityThread.main(ActivityThread.java:5480)
      at java.lang.reflect.Method.invoke(Method.java)
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
  Caused by: java.lang.IllegalStateException: Call `Realm.init(Context)` before calling this method.
      at io.realm.Realm.getDefaultInstance(Realm.java:208)
      at com.kimi.fastdb.PrefActivity.getRealmHelper(PrefActivity.java:1724)
      at com.kimi.fastdb.PrefActivity.onCreate(PrefActivity.java:270)
      at com.kimi.fastdb.LauncherActivity.onCreate(LauncherActivity.java:464)
      at android.app.Activity.performCreate(Activity.java:6308)
      at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2400)
  </code></pre>
  
  <p>Why the realm instance not been initialized after my Application starts?
  And how to fix it?</p>
  
  <p>Application:</p>
  
  <pre><code>public class App extends MultiDexApplication {
  
      @Override
      public void onCreate() {
          super.onCreate();
          Realm.init(this);
          RealmConfiguration realmConfiguration = new RealmConfiguration.Builder()
                      .schemaVersion( REALM_DATABASE_VERSION ) // Must be bumped when the schema changes
                      .migration( migration ) // Migration to run instead of throwing an exception
          //          .deleteRealmIfMigrationNeeded()
                      .build();
          Realm.compactRealm( realmConfiguration );
          Realm.setDefaultConfiguration(realmConfiguration);
  
      }
      ...
  }
  </code></pre>
  
  <p>AndroidManifest.xml</p>
  
  <pre><code>&lt;application
              android:name=".App"
              android:allowBackup="true"
              android:allowClearUserData="true"
              android:allowTaskReparenting="false"
              android:hardwareAccelerated="true"
              android:icon="@mipmap/ic_launcher"
              android:label="@string/app_name"
              android:largeHeap="true"
              android:theme="@style/SplashScreenTheme"&gt;
  ...
  
  &lt;/application&gt;
  </code></pre>