Classier Puzzlers - Java Puzzlers: Traps, Pitfalls, and Corner Cases - page 209

Solution 71: Import Duty
You might expect the program to print [1, 2, 3, 4, 5] , and indeed it would, if only it compiled.
Sadly, the compiler just can't seem to find the right toString method:
ImportDuty.java:9:Object.toString can't be applied to (Object[])
System.out.println(toString(args));
^
Is the compiler just being dense? Why would it try to apply Object.toString() , which doesn't
match the call's parameter list, when Arrays.toString(Object[]) matches perfectly?
The first thing the compiler does when selecting a method to be invoked at run time is to choose the
scope in which the method must be found [JLS 15.12.1]. The compiler chooses the smallest
enclosing scope that has a method with the right name. In our program, this scope is the class
ImportDuty , which contains the toString method inherited from Object . This scope has no
applicable method for the invocation toString(args) , so the compiler must reject the program.
In other words, the desired toString method isn't in scope at the point of the invocation. The
imported toString method is shadowed by a method with the same name inherited into
ImportDuty from Object [JLS 6.3.1]. Shadowing is a lot like obscuring ( Puzzle 68 ). The key
distinction is that a declaration can shadow another declaration only of the same kind: One type
declaration can shadow another, one variable declaration can shadow another, and one method
declaration can shadow another. By contrast, variable declarations can obscure type and package
declarations, and type declarations can obscure package declarations.
When one declaration shadows another, the simple name refers to the entity in the shadowing
declaration. In this case, toString refers to the toString method from Object . Simply put,
members that are naturally in scope take precedence over static imports. One consequence is
that static methods with the same name as Object methods cannot be used with the static import
facility.
Since you can't use static import with Arrays.toString , use a normal import declaration instead.
This is the way Arrays.toString was meant to be used:
import java.util.Arrays;
class ImportDuty {
static void printArgs(Object... args) {
System.out.println( Arrays. toString(args));