NAMES

Hiding Names

6.3.1

6.3.1   Hiding Names

Some declarations may be hidden ( 6.3.1) in part of their scope by another decla 

ration of the same name, in which case a simple name cannot be used to refer to

the declared entity.

The example:

class Test {

static int x = 1;

public static void main(String[] args) {

int x = 0;

System.out.print("x=" + x);

System.out.println(", Test.x=" + Test.x);

}

}

produces the output:

x=0, Test.x=1

This example declares:

a class

Test

a class (

static

) variable

x

 that is a member of the class

Test

a class method

main

 that is a member of the class

Test

a parameter

args

 of the

main

 method

a local variable

x

 of the

main

 method

Since the scope of a class variable includes the entire body of the class ( 8.2)

the class variable

x

 would normally be available throughout the entire body of the

method

main

. In this example, however, the class variable

x

 is hidden within the

body of the method

main

 by the declaration of the local variable

x

.

A local variable has as its scope the rest of the block in which it is declared

( 14.3.2); in this case this is the rest of the body of the

main

 method, namely its

initializer  

0

  and the invocations of

print

 and

println

.

This means that:

The expression  

x

  in the invocation of

print

 refers to (denotes) the value of

the local variable

x

.

The invocation of

println

 uses a qualified name ( 6.6)

Test.x

, which uses

the class type name

Test

 to access the class variable

x

, because the declara 

tion of

Test.x

 is hidden at this point and cannot be referred to by its simple

name.

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