7.5.2

Type Import on Demand Declaration

PACKAGES

Note that an import statement cannot import a subpackage, only a type. For

example, it does not work to try to import

java.util

 and then use the name

util.Random

 to refer to the type

java.util.Random

:

import java.util;

//

incorrect: compile time error

class Test { util.Random generator; }

7.5.2   Type Import on Demand Declaration

A

type import on demand declaration

 allows all

public

 types declared in the

package named by a fully qualified name to be imported as needed.

TypeImportOnDemandDeclaration:

import

PackageName

 . * ;

It is a compile time error for a type import on demand declaration to name a

package that is not accessible ( 6.6), as determined by the host system ( 7.2).

Two or more type import on demand declarations in the same compilation unit

may name the same package; the effect is as if there were exactly one such decla 

ration. It is not a compile time error to name the current package or

java.lang

 in

a type import on demand declaration, even though they are already imported; the

duplicate type import on demand declaration is ignored.

The example:

import java.util.*;

causes the simple names of all

public

 types declared in the package

java.util

to be available within the class and interface declarations of the compilation unit.

Thus, the simple name

Vector

 refers to the type

Vector

 in the package

java.util

 in all places where it is not hidden ( 6.3) by a single type import dec 

laration of a type whose simple name is

Vector

; by a type named

Vector

 and

declared in the package to which the compilation unit belongs; or by a declaration

of a field, parameter, or local variable named

Vector

. (It would be unusual for any

of these conditions to occur.)

7.5.3   Automatic Imports

Each compilation unit automatically imports each of the

public

type names

declared in the predefined package

java.lang

, as if the declaration:

import java.lang.*;

appeared at the beginning of each compilation unit, immediately following any

package

 statement.

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