问题
I am facing an issue with my app: If I deactivate within Android Studio Instant Run, my app crashes upon startup with the stacktrace:
12-29 13:36:37.876 4549-4549/com.mycoolapp.debug E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.mycoolapp.debug, PID: 4549
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.mycoolapp.debug/com.myapp.SplashScreenActivity}: java.lang.ClassNotFoundException: Didn't find class "com.myapp.SplashScreenActivity" on path: DexPathList[[zip file "/system/framework/android.test.runner.jar", zip file "/data/app/com.mycoolapp.debug-2/base.apk"],nativeLibraryDirectories=[/data/app/com.mycoolapp.debug-2/lib/arm, /vendor/lib, /system/lib]]
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2216)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2365)
at android.app.ActivityThread.access$800(ActivityThread.java:148)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1283)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5272)
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:909)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:704)
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.myapp.SplashScreenActivity" on path: DexPathList[[zip file "/system/framework/android.test.runner.jar", zip file "/data/app/com.mycoolapp.debug-2/base.apk"],nativeLibraryDirectories=[/data/app/com.mycoolapp.debug-2/lib/arm, /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:1065)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2206)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2365)
at android.app.ActivityThread.access$800(ActivityThread.java:148)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1283)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5272)
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:909)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:704)
Suppressed: java.lang.NoClassDefFoundError: com.myapp.SplashScreenActivity
at dalvik.system.DexFile.defineClassNative(Native Method)
at dalvik.system.DexFile.defineClass(DexFile.java:226)
at dalvik.system.DexFile.loadClassBinaryName(DexFile.java:219)
at dalvik.system.DexPathList.findClass(DexPathList.java:321)
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:54)
... 14 more
Suppressed: java.lang.ClassNotFoundException: com.myapp.SplashScreenActivity
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 far as I have researched this belongs to multidex: https://developer.android.com/studio/build/multidex.html
Even if I add the multiDexEnabled property to my gradle config the app crashes. Only if I enable InstantRun (which enables multidex in background), the app runs... If I create an apk the installation works, but the app crashes on startup with the same error.
Since I have as minSDK API Level 21, there should be no other change except of the multiDexEnabled property necessary, right?
回答1:
So last but not least my answer: All my configuration for multidex was correct... I don't know why, but after a complete OS restart everything works fine now... :)
回答2:
Just create new phone on AVD and try to install app on that phone. Hope it will work.
回答3:
The accepted answer was only a temporary fix for me, after altering code and a few builds the error came back.
After alot of trial and error the real problem was the jdk location my project was using, instead of using the embedded jdk in android studio i was using an installed version from oracle. After going to File > Project Structure > SDK Location and checking Use embedded JDK the problem was fixed for good.
回答4:
Check if your classpath
'com.android.tools.build:gradle:3.1.0-alpha05'
is up-to-date, had same problem and solved it with a full update.
来源：https://stackoverflow.com/questions/41382641/multidex-issue-java-lang-classnotfoundexception-didnt-find-class-on-path-dex