CODEWITHSUNDEEP
javaimport
kevin gomes
kevin gomes

Reputation: 1805

What will the following import declaration import?

java.io.Reader.*;

I know that Reader is a class, not a package.

So, what the above declaration will import?

Upvotes: 0

Views: 135

Answers (3)

Ted Hopp
Ted Hopp

Reputation: 234795

The declaration:

import java.io.Reader.*;

is an example of a type-import-on-demand declaration. From the Java Language Specification:

A type-import-on-demand declaration allows all accessible types of a named package or type to be imported as needed.

Since java.io.Reader contains no nested classes or other accessible types, the declaration would simply be ignored.

Note that Java also has an import static declaration. So

import static java.io.Reader.*;

would be an example of a static-import-on-demand declaration. Again, according to the Java Language Specification:

A static-import-on-demand declaration allows all accessible static members of a named type to be imported as needed.

And since java.io.Reader also has no accessible static members, the declaration would again be ignored.

Upvotes: 2

Shahbaz
Shahbaz

Reputation: 73

Statement 1 will include the Reader Class that you can use in your code, as this class is used to read the character stream

Statement 2 will include all the Classes from Reader.* Package ( if it is a package), i am assuming it generic

Upvotes: 1

Luigi Cortese
Luigi Cortese

Reputation: 11121

In the same file you can have both 

import java.io.Reader;          //Statement 1

import static java.io.Reader.*;        //Statement 2

the first one is importing only the class Reader from package java.io, the second one is importing all the static members of class Reader, wich appears to be only 

private static final int maxSkipBufferSize = 8192;

so, pretty useless, because being it private you cannot access it from your class, neither for reading nor for modifying

Upvotes: 2

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