Java Program to Check Whether Given String is palindrome or not

Check the given String is Palindrome or not?

If a string is palindrome, it gives the same string even after reversing it.

For example, malayalam, madam, liril etc.., are palindromes.

The following steps can be followed to check the string:

• Let the string be 'str'.
• Preserve a copy of the original string 'str' in another string 'temp'.
• Convert the string 'str' into a StringBuffer object 'sb'.
• Reverse the string in sb.
• Store the reversed string in 'str' again.
• Now, compare the original string 'temp' with the reversed string 'str' . If they equal the given string is palindrome, else not a palindrome.

We are converting a String into StringBuffer to use the reverse() method of StringBuffer class.

It is not possible to use methods of a class on the objects of another class.

Java code to check if the given string is palindrome or not:

import java.io.*;
class Programming9
{
  public static void main (String args[]) throws IOException
//IO Exception will thrown if an I/O errors occur
  {
    BufferedReader br = new BufferedReader (new InputStreamReader (System.in));	//accept String from keyboard
      System.out.println ("enter the String:");
    String str = br.readLine ();	//  read from BufferReader class
    String temp = str;		// converting the string into StringBuffer

    StringBuffer sb = new StringBuffer (str);
      sb.reverse ();		//reverse String into StringBuffer
      str = sb.toString ();	//convert StringBuffer into a String

    if (temp.equalsIgnoreCase (str))	//compare original string available in temp with this reversed String
        System.out.println (temp + " is palindrome");
    else
        System.out.println (temp + " is not palindrome");
  }
}

 Output:

enter the String:
Malayalam
Malayalam is palindrome

enter the String:
madam
madam is palindrome

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