It creates a stub, but you can also configure it to pass any method calls to original implementation. You should be tiping your hat i think.

https://javadoc.io/static/org.mockito/mockito-core/3.11.2/or...

User mock = mock(User.java)

Should have been

User mock = mock(User.class)

Ah oops, I've been writing exclusively Kotlin for several years, my Java is becoming rusty (no pun intended).