6.2

Names and Identifiers

NAMES

In the example:

class Test {

public static void main(String[] args) {

Class c = System.out.getClass();

System.out.println(c.toString().length() +

args[0].length() + args.length);

}

}

the identifiers

Test

,

main

, and the first occurrences of

args

 and

c

 are not names;

rather, they are used in declarations to specify the names of the declared entities.

The names

String

,

Class

,

System.out.getClass, System.out.println

,

c.toString

,

args

, and

args.length

 appear in the example. The first occur 

rence of

length

 is not a name, but rather an identifier appearing in a method invo 

cation expression ( 15.11). The second occurrence of

length

 is not a name, but

rather an identifier appearing in a method invocation expression ( 15.11).

The identifiers used in labeled statements and their associated

break

 and

continue

 statements are completely separate from those used in declarations.

Thus, the following code is valid:

class TestString {

char[] value;

int offset, count;

int indexOf(TestString str, int fromIndex) {

char[] v1 = value, v2 = str.value;

int max = offset + (count   str.count);

int start = offset + ((fromIndex < 0) ? 0 : fromIndex);

i:

for (int i = start; i <= max; i++)

{

int n = str.count, j = i, k = str.offset;

while (n   != 0) {

if (v1[j++] != v2[k++])

continue i;

}

return i   offset;

}

return  1;

}

}

This code was taken from a version of the class

String

 and its method

indexOf

( 20.12.26), where the label was originally called

test

. Changing the label to

have the same name as the local variable

i

 does not hide the label in the scope of

the declaration of

i

. The identifier

max

 could also have been used as the statement

label; the label would not hide the local variable

max

 within the labeled statement.

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