The following Java program application is a Palindrome Number. An integer is a Palindrome if it reads forward and backward in the same way, ignoring any leading minus sign. In this program, we use an input dialog box to get the input and an output dialog box to show the output. I will be using the JCreator IDE in developing the program.

To start in this tutorial, first open the JCreator IDE, click new and paste the following code

1. import
   
   javax.swing.JOptionPane
   
   ;
   
2. 
   
3. public
   
   class
   
   Palindrome
   
4. {
   
5. public
   
   static
   
   void
   
   main(
   
   String
   
   [
   
   ]
   
   args)
   
6. {
   
7. long
   
   num;
   
8. long
   
   temp;
   
9. 
   
10. String
    
    inputStr;
    
11. String
    
    outputStr;
    
12. 
    
13. inputStr =
    
14. JOptionPane
    
    .showInputDialog
    
    (
    
    "Enter an integer, "
    
15. +
    
    "positive or negative"
    
    )
    
    ;
    
16. 
    
17. num =
    
    Long
    
    .parseLong
    
    (
    
    inputStr)
    
    ;
    
18. temp =
    
    num;
    
19. 
    
20. if
    
    (
    
    num <=
    
    0
    
    )
    
21. {
    
22. num =
    
    -
    
    num;
    
23. inputStr =
    
    inputStr.valueOf
    
    (
    
    num)
    
    ;
    
24. 
    
25. }
    
26. if
    
    (
    
    isPalindrome (
    
    inputStr)
    
    )
    
27. outputStr =
    
    temp +
    
    " is a palindrome"
    
    ;
    
28. else
    
29. outputStr =
    
    temp +
    
    "is not a palindrome"
    
    ;
    
30. 
    
31. JOptionPane
    
    .showMessageDialog
    
    (
    
    null
    
    , outputStr,
    
32. "Palindrome Program"
    
    , JOptionPane
    
    .INFORMATION_MESSAGE
    
    )
    
    ;
    
33. System
    
    .exit
    
    (
    
    0
    
    )
    
    ;
    
34. }
    
35. public
    
    static
    
    boolean
    
    isPalindrome(
    
    String
    
    str)
    
36. {
    
37. int
    
    len =
    
    str.length
    
    (
    
    )
    
    ;
    
38. int
    
    i, j;
    
39. 
    
40. j =
    
    len -
    
    1
    
    ;
    
41. 
    
42. for
    
    (
    
    i =
    
    0
    
    ;
    
    i <=
    
    (
    
    len -
    
    1
    
    )
    
    /
    
    2
    
    ;
    
    i++
    
    )
    
43. {
    
44. if
    
    (
    
    str.charAt
    
    (
    
    i)
    
    !=
    
    str.charAt
    
    (
    
    j)
    
    )
    
45. return
    
    false
    
    ;
    
46. j--;
    
47. }
    
48. return
    
    true
    
    ;
    
49. 
    
50. }
    
51. }
    

Sample run#1:




sample run#2



The program algorithm are the following:

The first thing that the program does is read the integer.

Because the input of the program is string, the string containing the integer is converted into the integer.

If the integer is negative, the program changes it to positive.

The next step is to convert the integer back to a string and then determine whether the string is palindrome.