Field Initializations

[Kali Praveen]

I was looking at the following example in JLS and couldn't think of why
there is no compilation error on lines 9,10,21,22 where as there is compilation error on line 18. I could get the reasons for other errors except for the errors/non-errors on those lines.

1.class UseBeforeDeclaration {
2.static {
3.x = 100; // ok - assignment
4.int y = x + 1; // error - read before declaration
5.int v = x = 3; // ok - x at left hand side of assignment
6.int z = UseBeforeDeclaration.x * 2;
7.        // ok - not accessed via simple name
8.Object o = new Object(){ 
9.void foo(){x++;} // ok - occurs in a different class
10.{x++;} // ok - occurs in a different class
11.    };
12.  }
13.{
14.j = 200; // ok - assignment
15.j = j + 1; // error-right hand side reads before declaration
16.int k = j = j + 1; 
17.int n = j = 300; // ok - j at left hand side of assignment
18.int h = j++; // error - read before declaration
19.int l = this.j * 3; // ok - not accessed via simple name
20.Object o = new Object(){ 
21.void foo(){j++;} // ok - occurs in a different class
22.{ j = j + 1;} // ok - occurs in a different class
23.};
24.}
25.int w = x= 3; // ok - x at left hand side of assignment
26.int p = x; // ok - instance initializers may access static fields
27.static int u = (new Object(){int bar(){return x;}}).bar();
28.// ok - occurs in a different class
29.static int x;
30.int m = j = 4; // ok - j at left hand side of assignment
31.int o = (new Object(){int bar(){return j;}}).bar(); 
32.// ok - occurs in a different class
33.int j;
34.}

Thanks,
Praveen