分支语句的注意事项

public static void main(String[] args) {
      boolean b = true;
      if (b == false)
         System.out.println("a");
      else if (b)
         System.out.println("b");

      else if (!b)
         System.out.println("c");
      else
         System.out.println("d");
   }

public static void main(String[] args) {

      int x = 2;

      int y = 3;

      switch (x) {

      default:

         y++;

      case 3:

         y++;

      case 4:

         y++;

      }

      System.out.println("y=" + y);

   }