java基本输入输出，回文串

package the1;
import java.util.Scanner;
import javax.swing.JOptionPane;
//import java.util.Strin

public class huiwenchuan {

	public static void main(String[] args) {
		// TODO Auto-generated method st
		//System.out.printf("为何不能输出");
		Scanner s=new Scanner(System.in);
		String a=s.next();
		StringBuffer b=new StringBuffer(a);
	    b.reverse();
	    String c=b.toString();
	    if(a.equals(c)==true) {
	    	System.out.printf("%s是回文串\n",a);
	    	//OptionPane.showMessageDialog(null,"是回文串",JOptionPane.INFORMATION_MESSAGE);
	    }else {
	    	System.out.printf("%s不是回文串\n",a);
	    }
		
		

	}

}