In this program, you'll learn to check whether a number is palindrome or not in Java. This is done by using for and while loop.

```
public class Palindrome {
public static void main(String[] args) {
int num = 121, reversedInteger = 0, remainder, originalInteger;
originalInteger = num;
// reversed integer is stored in variable
while( num != 0 )
{
remainder = num % 10;
reversedInteger = reversedInteger * 10 + remainder;
num /= 10;
}
// palindrome if orignalInteger and reversedInteger are equal
if (originalInteger == reversedInteger)
System.out.println(originalInteger + " is a palindrome.");
else
System.out.println(originalInteger + " is not a palindrome.");
}
}
```

When you run the program, the output will be:

121 is a palindrome number.

In this program,

- First, given number (
`num`)'s value is stored in another integer variable,`originalInteger`. This is because, we need to compare the values of reversed number and original number at the end. - Then, a while loop is used to loop through num until it is equal to 0.
- On each iteration, the last digit of
`num`is stored in`remainder`. - Then,
`remainder`is added to`reversedInteger`such that it is added to the next place value (multiplication by 10). - Then, the last digit is removed from
`num`after division by 10.

- On each iteration, the last digit of
- Finally,
`reversedInteger`and`originalInteger`are compared. If equal, it is a palindrome number. If not, it isn't.

Here are the execution steps that takes place:

num | num != 0 | remainder | reversedInteger |
---|---|---|---|

121 | true | 1 | 0 * 10 + 1 = 1 |

12 | true | 2 | 1 * 10 + 2 = 12 |

1 | true | 1 | 12 * 10 + 1 = 121 |

0 | false | - | 121 |

```
public class Palindrome {
public static void main(String[] args) {
int num = 11221, reversedInteger = 0, remainder, originalInteger;
originalInteger = num;
// reversed integer is stored in variable
for( ;num != 0; num /= 10 )
{
remainder = num % 10;
reversedInteger = reversedInteger * 10 + remainder;
}
// palindrome if orignalInteger and reversedInteger are equal
if (originalInteger == reversedInteger)
System.out.println(originalInteger + " is a palindrome.");
else
System.out.println(originalInteger + " is not a palindrome.");
}
}
```

When you run the program, the output will be:

11221 is not a palindrome.

In the above program, for loop is used instead of a while loop.

On each iteration, `num /= 10`

is executed and condition `num !=0`

is checked.

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