Does Java optimize method calls via an interface which has a single implementor marked as final?

Question

If I have a reference to a class and invoke a method on it, and the class or the method is final, my understanding is that the compiler or the JVM would replace the dynamic dispatch with a cheaper static dispatch since it can determine exactly which version would be invoked.

However, what if I have a reference to an interface, and the interface currently has only a single implementor, and that implementor is final or the method is final in that implementor, can the JVM figure that out at runtime and optimize these calls?

Answer 1

(Insert Knuth quote here about optimization.)

See Wikis Home > HotSpot Internals for OpenJDK > PerformanceTechniques.

• Methods are often inlined. This increases the compiler's "horizon" of optimization.
• Static, private, final, and/or "special" invocations are easy to inline.
• Virtual (and interface) invocations are often demoted to "special" invocations, if the class hierarchy permits it. A dependency is registered in case further class loading spoils things.
• Virtual (and interface) invocations with a lopsided type profile are compiled with an optimistic check in favor of the historically common type (or two types).

There are some interesting links from Inlining.