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class Super { static int taxi = 1729; }
class Sub extends Super {
static { System.out.print("Sub "); }
}
class Test {
public static void main(String[] args) {
System.out.println(Sub.taxi);
}
}
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A reference to a class field causes initialization of only the class or interface
that actually declares it, even though it might be referred to through the name of a
subclass, a subinterface, or a class that implements an interface.
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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;
}
}
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1
j=3
jj=4
3
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Initialization of an interface does not, of itself, cause initialization of any of its
superinterfaces.
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.