EXPRESSIONS

Array Creation Expressions

15.9

15.8.2   Example: Evaluation Order and Out of Memory Detection

If evaluation of a class instance creation expression finds there is insufficient

memory to perform the creation operation, then an

OutOfMemoryError

 is thrown.

This check occurs before any argument expressions are evaluated.

So, for example, the test program:

class List {

int value;

List next;

static List head = new List(0);

List(int n) { value = n; next = head; head = this; }

}

class Test {

public static void main(String[] args) {

int id = 0, oldid = 0;

try {

for (;;) {

++id;

new List(oldid = id);

}

} catch (Error e) {

System.out.println(e + ", " + (oldid==id));

}

}

}

prints:

java.lang.OutOfMemoryError: List, false

because the out or memory condition is detected before the argument expression

oldid = id

 is evaluated.

Compare this to the treatment of array creation expressions ( 15.9), for which

the out of memory condition is detected after evaluation of the dimension expres 

sions ( 15.9.3).

15.9   Array Creation Expressions

An array instance creation expression is used to create new arrays ( 10).

ArrayCreationExpression:

new

PrimitiveType DimExprs Dims

opt

new

TypeName DimExprs Dims

opt

315