Andriod API < 24 -> NoClassDefFoundError: Failed resolution of: Ljava/util/Optional;

[yogurtearl]

With mockito-android 3.5.15 on Android API 23 we are getting this error below, it works fine with 3.4.6

Turning on coreLibraryDesugaring would likely fix this for API 23, but that might not be a viable option for all builds.
https://developer.android.com/studio/releases/gradle-plugin#j8-library-desugaring

java.util.Optional wasn't added to Android until API 24 (see the Android docs for which API level a given class or method was added in):
https://developer.android.com/reference/java/util/Optional

Stacktrack.

at org.mockito.plugins.MockMaker$-CC.$default$createSpy(MockMaker.java:93)
at com.android.dx.mockito.DexmakerMockMaker.createSpy(DexmakerMockMaker.java)
at org.mockito.internal.util.MockUtil.createMock(MockUtil.java:45)
at org.mockito.internal.MockitoCore.mock(MockitoCore.java:61)
at org.mockito.Mockito.spy(Mockito.java:2033)
at com.nhaarman.mockitokotlin2.SpyingKt.spy(Spying.kt:52)

...

Caused by: java.lang.ClassNotFoundException: Didn't find class "java.util.Optional" on path: DexPathList[[zip file "/system/framework/android.test.runner.jar", zip file "/data/app/com.example.test-1/base.apk", 6, /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)
... 46 more
Suppressed: java.lang.ClassNotFoundException: java.util.Optional
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)
... 47 more
Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack trace available

[TimvdLippe]

Is this a duplicate of #2007?

[alsutton]

I think it's something different because we're seeing a very similar issue and have pinned the version of objenesis to 2.6.

We have the following hierarchy; InterfaceA -> InterfaceB -> InterfaceC<Type>, using 3.5.13 we see;

Run all tests in project; Two test classes fail to create mocks of InterfaceA, with NoClassDefFoundError for InterfaceA$MockitoMock$1225627330
Run all test methods in both classes; All tests pass
Run individual test methods; All tests pass

Using 3.4.6 all tests pass in all three scenarios.

We've create a workaround which is to create a fake class which implements InterfaceA and then mock that, which works in 3.5, but it seems a nasty hack.

When I was creating the fake I did see a NoClassDefFoundError for InterfaceC, which comes from a different gradle project, but I ruled out dependency path issues because the individual classes and methods complete their run, it's only running all the tests in the main project that causes those classes and methods to fail.

[yogurtearl]

@TimvdLippe this is because Mockmaker is using java.util.Optional.

mockito/src/main/java/org/mockito/plugins/MockMaker.java

Line 93 in e098342

return Optional.empty();

If you want to support API 23 and older on Android, with coreLibraryDesugaring turned off (which is the default), you can't use java.util.Optional at all.

[TimvdLippe]

I am closing this as WontFix, since Android API level 23 was released over 6 years ago. For older Android APIs, we suggest users to stick to Mockito 2. With Mockito 3, we require Java 8, which has similar limitations to the Android ecosystem with respect to API level.