Nasty UnIndented Nests
Write truth tables for the following pieces of Java code; 
note that a, b are boolean conditions and Y, Z are actions, such as output.
   1. if (a) if (b) Y; else Z;
   2. if (a) {if (b) Y;} else Z;
   3. if (a) Y; else if (b) Z;
   4. if (a && b) Y; else Z;

The Truth tables:
   a  b  1  2  3  4
   F  F  -  Z  -  Z
   F  T  -  Z  Z  Z
   T  F  Z  -  Y  Z
   T  T  Y  Y  Y  Y

If you would want to check the above tables
here is code to create such a truth tables

class NestedLogic1 {
// Does show truth table for 2 booleans a, b

   public static void main (String args[]) {

   boolean a, b;

   a = false;
   while (true) {

      b = false;
      while (true) {

         System.out.print (a + " ");
         System.out.print (b + " ");

         if (a) 
            if (b) 
               System.out.print ("Y");
            else 
               System.out.print ("Z");

         System.out.println (" ");

      if (b) break;
         b = ! b;
      }//EndWhile b

   if (a) break;
   a = ! a;
   }//EndWhile a

   }//EndRoutine main

}//EndClass NestedLogic