How to resolve ClassNotFoundException in Android Studio

Issue

I have recently migrated my project from Eclipse to Android Studio. Earlier everything was working perfectly, but recently when I started working on it again I am not able to launch the application. Its always showing me the same error. I haven't changed anything on application level, still getting the same result. Here is the log I am getting

FATAL EXCEPTION: main
Process: com.example.android, PID: 6977
java.lang.RuntimeException: Unable to instantiate application com.example.android.MobApplication: java.lang.ClassNotFoundException: Didn't find class "com.example.android.MobApplication" on path: DexPathList[[zip file "/data/app/com.example.android-1/base.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]]
at android.app.LoadedApk.makeApplication(LoadedApk.java:601)
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4919)
at android.app.ActivityThread.access$1500(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1424)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:155)
at android.app.ActivityThread.main(ActivityThread.java:5721)
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:1029)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:824)
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.android.MobApplication" on path: DexPathList[[zip file "/data/app/com.example.android-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.newApplication(Instrumentation.java:986)
at android.app.LoadedApk.makeApplication(LoadedApk.java:587)
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4919) 
at android.app.ActivityThread.access$1500(ActivityThread.java:144) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1424) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:155) 
at android.app.ActivityThread.main(ActivityThread.java:5721) 
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:1029) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:824) 
Suppressed: java.lang.ClassNotFoundException: com.example.android.MobApplication
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

As I have recently switched my IDE I am facing problems to solve this one. I have also tried the other answers but still unable to solve this error. Kindly help me with this so I can proceed with my project. Any help would be appreciable. Thanks

Solution

This might be the 65k methods limit. Try to use the solutions in the link.

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Edit: For others who stumble this issue - @Salman Khan added multiDexEnabled true to the gradle file (as written in the link) and it solved the problem. It would be still better to read the whole article and follow the steps there.

Answered By - Uriel Frankel