title: Java.lang.ClassNotFoundException after Android studio update
body: <p>I updated to Android Studio 2.1 from the stable channel. As soon as I did that I am getting ClassNotFoundException to my login class, which is declared in the manifest for long time. Prior to the update my app was compiling fine. </p>
  
  <pre><code>com.myapp E/AndroidRuntime: FATAL EXCEPTION: main
      Process: com.myapp, PID: 29605
      java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.myapp/com.myapp.Login}: java.lang.ClassNotFoundException: Didn't find class "com.myapp.Login" on path: DexPathList[[zip file "/data/app/com.myapp-1/base.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]]
      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3023)
      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3294)
      at android.app.ActivityThread.access$1000(ActivityThread.java:210)
      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1704)
      at android.os.Handler.dispatchMessage(Handler.java:102)
      at android.os.Looper.loop(Looper.java:145)
      at android.app.ActivityThread.main(ActivityThread.java:6938)
      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:1404)
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
      Caused by: java.lang.ClassNotFoundException: Didn't find class "com.myapp.Login" on path: DexPathList[[zip file "/data/app/com.myapp-1/base.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]]
      at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
      at android.app.Instrumentation.newActivity(Instrumentation.java:1094)
      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3013)
      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3294) 
      at android.app.ActivityThread.access$1000(ActivityThread.java:210) 
      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1704) 
      at android.os.Handler.dispatchMessage(Handler.java:102) 
      at android.os.Looper.loop(Looper.java:145) 
      at android.app.ActivityThread.main(ActivityThread.java:6938) 
      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:1404) 
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199) 
      Suppressed: java.lang.ClassNotFoundException: com.myapp.Login
      at java.lang.Class.classForName(Native Method)
      at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
      at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
      ... 13 more
      Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack available
  </code></pre>
  
  <p>This is my gradle.build</p>
  
  <pre><code>apply plugin: 'com.android.application'
  apply plugin: 'com.google.gms.google-services'
  android {
      compileSdkVersion 'Google Inc.:Google APIs:23'
      buildToolsVersion "22.0.1"
  
      defaultConfig {
          applicationId "com.myapp"
          minSdkVersion 14
          targetSdkVersion 22
      }
  
      buildTypes {
          release {
              minifyEnabled false
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
          }
      }
  }
  
  dependencies {
  //    compile files('libs/smack-core-4.0.7.jar')
      compile 'com.android.support:appcompat-v7:23.0.1'
      compile 'com.google.android.gms:play-services:7.8.0'
      compile 'com.google.maps.android:android-maps-utils:0.4+'
  }
  </code></pre>
  
  <p>So far I have tried
  1)Clean and rebuild project
  2)Delete the build folder and rebuild project/restart Android Studio
  3)Switch to canary channel as well as dev channel and update
  4)Check and uncheck the offline mode in Settings
  Obviously this is a bug, but is there a solution to this? How can I reverse the recent updates? Any help is much appreciated. </p>