CLASSES

Class Declaration

8.1

the fully qualified name of the class

Point

 is

vista.Point

. (The package name

vista

 is suitable for local or personal use; if the package were intended to be

widely distributed, it would be better to give it a unique package name ( 7.7).)

A compile time error occurs if the

Identifier

naming a class appears as the

name of any other class type or interface type declared in the same package ( 7.6).

A compile time error occurs if the

Identifier

 naming a class is also declared as

a type by a single type import declaration ( 7.5.1) in the compilation unit ( 7.3)

containing the class declaration.

In the example:

package test;

import java.util.Vector;

class Point {

int x, y;

}

interface Point {

//

compile time error #1

int getR();

int getTheta();

}

class Vector { Point[] pts; }

//

compile time error #2

the first compile time error is caused by the duplicate declaration of the name

Point

 as both a

class

 and an

interface

 in the same package. A second error

detected at compile time is the attempt to declare the name

Vector

 both by a class

type declaration and by a single type import declaration.

Note, however, that it is not an error for the

Identifier

 that names a class also

to name a type that otherwise might be imported by a type import on demand

declaration ( 7.5.2) in the compilation unit ( 7.3) containing the class declaration.

In the example:

package test;

import java.util.*;

class Vector { Point[] pts; }

//

not a compile time error

the declaration of the class

Vector

 is permitted even though there is also a class

java.util.Vector

. Within this compilation unit, the simple name

Vector

 refers

to the class

test.Vector

, not to

java.util.Vector

 (which can still be referred

to by code within the compilation unit, but only by its fully qualified name).

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