java字符串索引超出边界异常？

Question

我的任务是反转字符串并打印反转的字符串

这是我的密码

import java.util.*;
import java.io.*;
public class reverse1
{
  public static void reverse(String x) throws IllegalCharacterException
  {
    char j;
    int max;
    String reversedString = " ";
    for(int i = 0; i < x.length() - 1; i++)
    {
      max = x.length();
      j = x.charAt(i);
      j = reversedString.charAt(max);
      i--;
    }//end for loop

   }//end method

 public static void main(String[] args) throws IllegalCharacterException
 {
   Scanner keyboard = new Scanner(System.in);
   String s;
   System.out.println("Please enter a string");
   s = keyboard.next();
   reverse(s);
 }//end main

}//end class

我一直在犯这样的错误：

java.lang.StringIndexOutOfBoundsException: String index out of range: 6
at java.lang.String.charAt(Unknown Source)
at reverse1.reverse(reverse1.java:14)
at reverse1.main(reverse1.java:26)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at edu.rice.cs.drjava.model.compiler.JavacCompiler.runCommand(JavacCompiler.java:272)

我检查了上面提到的行号，但仍然不明白问题所在。我确实把x.length（）改成了x.length（）-1，因为一个朋友告诉我要这么做，但我总是会遇到同样的错误