public class stringfanzhaun {

    public static void main(String[] args) {

        String str="12345";

        char[] qq=str.toCharArray();

        String pp="";

        for(int i=qq.length-1;i>=0;i--){

            pp=pp+qq[i];

        }

        System.out.println(pp);

    }

}

public class stringfanzhaun {

    public static void main(String[] args) {

        stringfanzhaun aa=new stringfanzhaun();

        String str="12345";

        String hello=aa.fan(str);

                System.out.println(hello.toString());

    }

    public String fan(String str){

        if(str==null||str.length()==0){

            return str;

        }

        int len=str.length();

        if(len==1){

            return str;

        }else{

            return fan(str.substring(1))+str.charAt(0);

        }

    }

}