Program for palindrom string check in java

import java.io.*;
public class pali_string
{
public static void main()throws IOException
{
InputStreamReader isr=new InputStreamReader(System.in);
BufferedReader br=new BufferedReader(isr);
char ch;
String s1,s2="";
int i,j;
System.out.println("Enter the string");
s1=br.readLine();
i=s1.length();
for(j=i-1;j>=0;j--)
{
ch=s1.charAt(j);
s2=s2+ch;
}
if(s1.compareToIgnoreCase(s2) == 0)
System.out.println("Palindrome="+s2);
else
System.out.println("not a palindrome");
}
}