java && and閘 判斷大小寫

package cc.home;
public class LetterCheck2 {
 public static void main(String[] args) {

   char symbol = 'A' ;  //設定為字元
         symbol = (char)(128.0*Math.random());  //隨機產生0-127隨機字元
         if(symbol >= 'A' && symbol <= 'Z' ){
          System.out.println("大寫 " + symbol);
         
         }
         else {
          if(symbol >= 'a' && symbol<= 'z') {
           System.out.println("小寫 " +symbol);
          }
          else {
           System.out.println("The code is not a letter");
          }
         }
 }
}