java判斷是不是迴文字符及逆向數出方法

//迴文字符串判斷
public class PalindromeTest {  
  
   public static void main(String[] args) {  
           isPalidrome("abcdedcba") ;  
    }  
  
   public static void isPalidrome(String str){  
       char[] ch = str.toCharArray();  
       int len = ch.length;  
       for (int i = 0, int j = len - 1; i <= j;) {  
           if (ch[i++] == ch[j--]) {  
           } else {  
                System.out.println("this string is not palindrome!");  
                break;  
          }  
       }  
   }  
} 
//字符串逆向輸出的方法
public class InverseString {  
    public static void main(String[] args) {  
        String str = "fdsadsasssggg";  
        System.out.println(inverseString(str));  
    }  
  
    public static String inverseString(String s) {  
        char[] a = new char[s.length()];  
        char[] temp = s.toCharArray();  
        for (int i = temp.length-1,j=0; i >=0;) {  
            a[j++] = temp[i--];  
        }  
        return String.valueOf(a);  
    }  
}