Why isn't a qualified static final variable allowed in a static initialization block?

Question

Case 1

class Program {     static final int var;      static {         Program.var = 8;  // Compilation error     }      public static void main(String[] args) {         int i;         i = Program.var;         System.out.println(Program.var);     } } 

Case 2

class Program {     static final int var;      static {         var = 8;  //OK     }      public static void main(String[] args) {         System.out.println(Program.var);     } } 

Why does Case 1 cause a compilation error?

Answer 1

The JLS holds the answer (note the bold statement):

Similarly, every blank final variable must be assigned at most once; it must be definitely unassigned when an assignment to it occurs. Such an assignment is defined to occur if and only if either the simple name of the variable (or, for a field, its simple name qualified by this) occurs on the left hand side of an assignment operator. [§16]

This means that the 'simple name' must be used when assigning static final variables - i.e. the var name without any qualifiers.

Answer 2

Apparently this is a cheap syntactic trick to limit definite (un)assignment analysis within the class itself.

If the field is syntactically qualified with a class name, the code is usually in another class, where the analysis cannot reach.

This trick fails in your example. Other examples of oddity:

static class A {     static final int a;     static     {         // System.out.println(a); // illegal         System.out.println(A.a);  // compiles!         a = 1;     } } 

If they had more resources, they probably would've made a finer rule. But we can't change spec now.