`mockStatic` fails with `class redefinition failed: invalid class` about mockito

[jkim323]

Although I am unfamiliar to the the Thales JCPROV library, I am a bit curious on this issue. I am wondering if you have tried checking if your class is missing in your class path by simply trying to use the static method before mocking it because this has happened to me once before. But based on your issue since you are work involves with native code maybe mocking the native methods is not the best route because I have heard of challenges on doing this. Have you tried exploring doing something like encapsulating it in a wrapper class or in an interface?

[scordio]

Yes, the library is in the classpath: if I call one of the methods without mocking, it fails in the static initialization block with a missing native library error, as expected.

Also yes, wrapping works fine as a workaround. In addition, there is another class (still part of the library) that offers similar static methods, wrapping each native call with exception throwing in case of errors, and mocking this class works as expected.

[jkim323]

Interesting. Does the other successful class also share the same characteristics as the class you are having problems with or are there differences? I am wondering if two classes share the last bullet you mentioned in the post. Also, have you explored using PowerMock perhaps?

[scordio]

No, they are not the same. The successful one:

• Is also public, top level and non-final
• Has also default constructor that is private and does nothing
• Has public methods that are all static but not native
• Has no static initialization block (i.e., no load of a native library)

Imagine something like:

public class NativeClass {

  private NativeClass() {}

  public static native int method();

  static {
    System.loadLibrary("native");
  }

}

public class WrapperClass {

  private WrapperClass() {}

  public static int method() {
    int result = NativeClass.method();
    if (result != 0) throw new RuntimeException(result);
  }

}

(written without checking the original code – beware of typos 🙂 )

[jkim323]

After reading your difference , it makes sense to why you are seeing it fail because it seems like a common known issue that Mockito is unable to mock native methods; it is currently a limitation on Mockito as of now. Perhaps you can try PowerMock as an alternative solution but I am not aware of a definitive solution.. unless we develop on this maybe creating a discussion on this topic might help.