Difference between java.util.Scanner and java.util.Scanner.*

java

Solution

import java.util.Scanner;

This imports `Scanner` (as you already know).

import java.util.Scanner.*;

This imports any public nested classes defined within `Scanner`.

This particular import statement is useless, as `Scanner` does not define any nested classes (and the import does not import `Scanner` itself). However, this can be used with something like `import java.util.Map.*`, in which case `Entry` (an interface nested in `Map` that is commonly used when dealing with maps) will be imported. I'm sure there are better examples, this is just the one that came to mind.

All of this is specified in JLS §7.5 (specifically, see §7.5.1: Single-Type-Import Declarations).

In response to the OP's edit:

Ok so import `java.util.Scanner.*` imports the public nested classes. But what if there was also a package called `Scanner`? What would the statement `import java.util.Scanner.*` do then?

In this case there would be a compilation error, since the package `java.util.Scanner` would collide with the type `java.util.Scanner`.

Problem

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