This kind of function overload is present everywhere in the Java collection framework (and probably other libraries). It is a performance optimization (variadic arguments in Java require creating an array), and variadiac overloads also exist (Map.of needs a list of Map.Entry for type safety) for creating collections of any size.

https://docs.oracle.com/en/java/javase/11/docs/api/java.base...

Do note that the created map is immutable. However, you could pass the created map to the constructor HashMap (or another type) to obtain a mutable copy of the Map created using Map.of