import javax.swing.JOptionPane; 
public class ReverseString { 
   
  public static void main (String args[]){ 
    String originalString; 
    String resultString = "";   
     
    originalString = JOptionPane.showInputDialog("Please input a String: "); 
     
    char[] charArray = originalString.toCharArray(); 
   
    for (int i=charArray.length-1; i>=0; i--){ 
      resultString += charArray[i]; 
    } 
     
    JOptionPane.showMessageDialog(null, resultString, "Reverse String", JOptionPane.INFORMATION_MESSAGE); 
  } 
} 

import javax.swing.JOptionPane; 
public class ReverseString { 
  public static void reverseString (String str){ 
    if (str.length() == 1){ 
      System.out.print(str); 
    } 
    else{ 
      String subString1 = str.substring(0, str.length()-1); 
      String subString2 = str.substring(str.length()-1); 
       
      System.out.print(subString2); 
       
      reverseString (subString1);      
    } 
  } 
   
  public static void main (String args[]){ 
    String originalString; 
     
    originalString = JOptionPane.showInputDialog("Please input a String: "); 
     
    reverseString (originalString);    
  } 
} 

import javax.swing.JOptionPane; 
public class ReverseString { 
  public static void reverseString (String str){ 
    StringBuffer stringBuffer = new StringBuffer (str); 
     
    System.out.print(stringBuffer.reverse()); 
  } 
   
  public static void main (String args[]){ 
    String originalString; 
     
    originalString = JOptionPane.showInputDialog("Please input a String: "); 
     
    reverseString (originalString);     
  } 
}