[AndrewBissell]

Not having to think about the question "should I make this method virtual?" makes the Java language simpler, yes.

In the vast majority of cases where a virtual function call is actually monomorphic or bimorphic at runtime, the JVM JIT can observe that and potentially inline the method (with an if statement in the bimorphic case). It puts guards around the inlined method and deoptimizes in the event that a newly loaded class renders the optimization incorrect.

[MichaelGG]

It just flips it for "should I make this method final?" So at best it's a wash. In the majority of cases, a function shouldn't be virtual so users need to mark it final to accurately represent their design.

[AndrewBissell]

Well, the answer to "should I make x final" is always "yes" in Java, so you don't really have to think too hard about that either. :-) `final` really should have been the default setting for all methods, classes, and local variables, but unfortunately inheritance was still in vogue when Java was created, and the benefits of immutable values weren't as well understood or appreciated either (or maybe they just figured the C & C++ programmers they were trying to win over would hate it).