CLASSES

Examples of Field Declarations

8.3.3

sample.printBoth();

System.out.println(sample.x + " " +

((Point)sample).x);

}

}

then the field

x

 of class

Point

 is no longer hidden within class

Test

. Within

instance methods in the declaration of class

Test

, the simple name

x

 now refers to

the field declared within class

Point

. Code in class

Test

 may still refer to that

same field as

super.x

. The expression

sample.x

 still refers to the field

x

 within

type

Test

, but that field is now an inherited field, and so refers to the field

x

declared in class

Point

. The output from this variant program is:

2 2

2 2

8.3.3.3

Example: Multiply Inherited Fields

A class may inherit two or more fields with the same name, either from two inter 

faces or from its superclass and an interface. A compile time error occurs on any

attempt to refer to any ambiguously inherited field by its simple name. A qualified

name or a field access expression that contains the keyword

super

 ( 15.10.2) may

be used to access such fields unambiguously. In the example:

interface Frob { float v = 2.0f; }

class SuperTest { int v = 3; }

class Test extends SuperTest implements Frob {

public static void main(String[] args) {

new Test().printV();

}

void printV() { System.out.println(v); }

}

the class

Test

 inherits two fields named

v

, one from its superclass

SuperTest

 and

one from its superinterface

Frob

. This in itself is permitted, but a compile time

error occurs because of the use of the simple name

v

 in method

printV

: it cannot

be determined which

v

 is intended.

The following variation uses the field access expression

super.v

 to refer to

the field named

v

 declared in class

SuperTest

 and uses the qualified name

Frob.v

 to refer to the field named

v

 declared in interface

Frob

:

interface Frob { float v = 2.0f; }

class SuperTest { int v = 3; }

class Test extends SuperTest implements Frob {

public static void main(String[] args) {

new Test().printV();

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