Switch statement and case variables

Question

Since constant variables do not have to be initialized when declared, they could be initialized later based on conditional logic and used to make the Switch statement more useful by using them as case labels. Well, sounds good in theory but I can't find anyway to make it work.
I can't even get this to compile when the value of the case label is obvious at compile time :
public class Switchtest
public static void main(String[] args)
int test = 0;
final int x;
x = 1;
switch (test)
case x: System.out.println("case x " );break;
default: System.out.println("Default ");break;
It gives an error about expecting x to be constant. I've tried static initializer blocks, etc. Is there anyway to have the case label variables initialized at runtime to make the Switch statement more useful?

Answer 1

If jvm can use a hashtable for a switch statement. This hashtable is as constant as the compiled code, i.e., it can be defined at compile- time and it con not be modified runtime. Therefore a switch- case construction is faster than an else-if construction. But the strength of else- if is that it is more flexible. If you want to test on multiple variable values, you must use else-if
class a
   public int method()
      int val = (int)(Math.random()*3);
      int x;
      if(val == 0)
         x = 1;
      else if(val == 1)
         x = 2;
      else
         x = 3;
      return x;
class b
   public int method()
      int val = (int)(Math.random()*3);
      int x;
      switch (val)
         case 0:
            x = 1;
            break;
         case 1:
            x = 2;
            break;
         default:
            x = 3;
            break;
      return x;
}b is bigger than a, but also faster. The technique used in a is more flexible, but b uses O(1) time where a uses O(n). (where n is the number of cases/else-ifs)