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When Initialization Occurs

 
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Bartender,
This is actually a response to Isabel's question in the thread called Mock Exam Dan - Initialization A (Topic). When I tried to post a reply in that thread I got the following error message. "Member profile corrupt (blank): '00035013'"
Isabel,
The following is a quotation from
The Java Language Specification, Section 12.4.1, When Initialization Occurs.


A class or interface type T will be initialized immediately before the first occurrence of any one of the following:
...
A static field declared by T is used and the reference to the field is not a compile-time constant (�15.28). References to compile-time constants must be resolved at compile time to a copy of the compile-time constant value, so uses of such a field never cause initialization.


Use of a compile time-constant does not result in the initialization of the interface.
 
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Hi There:
I had the same problem. Here is one example that
explains it more:


Initialization of an interface does not, of itself, cause initialization of any of its superinterfaces.
Thus, the test program:

interface I {
int i = 1, ii = Test.out("ii", 2);
}
interface J extends I {
int j = Test.out("j", 3), jj = Test.out("jj", 4);
}
interface K extends J {
int k = Test.out("k", 5);
}
class Test {
public static void main(String[] args) {
System.out.println(J.i);
System.out.println(K.j);
}
static int out(String s, int i) {
System.out.println(s + "=" + i);
return i;
}
}
produces the output:
1
j=3
jj=4
3

The reference to J.i is to a field that is a compile-time constant; therefore, it does not cause I to be initialized. The reference to K.j is a reference to a field actually declared in interface J that is not a compile-time constant; this causes initialization of the fields of interface J, but not those of its superinterface I, nor those of interface K. Despite the fact that the name K is used to refer to field j of interface J, interface K is not initialized.


[ August 28, 2002: Message edited by: Barkat Mardhani ]
[ August 28, 2002: Message edited by: Barkat Mardhani ]
 
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Thanks a lot U both
PS: I'm enjoying a lot this forum... all people here are very gentile and helpful!!!
 
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