Sybex 816 - page 129: Map.of is not overloaded with odd parameter number

[Jos Roseboom]

The text on Map.of says Map.of("key1", "value1", "key2"); compiles and throws runtime error, but it does not compile. Map.of is only overloaded with even parameter numbers https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/Map.html

[Campbell Ritchie]

No, it is only overloaded to take pairs of “K”s and “V”s. It goes K, V or K, V, K, V or K, V, K, V, K, V, K, V etc.. So you can't have odd numbers of parameters, Where does it say such code compiles?

[Jos Roseboom]

On page 129 in the section on Map.of() and Map.copyOf() is the fragment:

Map.of("key1", "value1", "key2"); // INCORRECT

Right below that fragment the first line says:

This code compiles but throws an error at runtime.

[Campbell Ritchie]

Aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaah! Is that where it comes from? Now I understand the problem. Thank you.

[Jeanne Boyarsky]

Confirmed and added to the errata