EXPRESSIONS

Argument Lists are Evaluated Left to Right

15.6.4

class Test {

public static void main(String[] args) {

double d = 8e+307;

System.out.println(4.0 * d * 0.5);

System.out.println(2.0 * d);

}

}

prints:

Infinity

1.6e+308

because the first expression overflows and the second does not.

In contrast, integer addition and multiplication

are

 provably associative in

Java; for example

a+b+c

, where

a

,

b

, and

c

 are local variables (this simplifying

assumption avoids issues involving multiple threads and

volatile

 variables),

will always produce the same answer whether evaluated as

(a+b)+c

 or

a+(b+c)

;

if the expression

b+c

 occurs nearby in the code, a smart compiler may be able to

use this common subexpression.

15.6.4   Argument Lists are Evaluated Left to Right

In a method or constructor invocation or class instance creation expression, argu 

ment expressions may appear within the parentheses, separated by commas. Each

argument expression appears to be fully evaluated before any part of any argument

expression to its right.

Thus:

class Test {

public static void main(String[] args) {

String s = "going, ";

print3(s, s, s = "gone");

}

static void print3(String a, String b, String c) {

System.out.println(a + b + c);

}

}

always prints:

going, going, gone

because the assignment of the string

"gone"

 to

s

 occurs after the first two argu 

ments to

print3

 have been evaluated.

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