One of the interesting Java coding interview question for freshers and beginners. A number is palindrome if its equal to reverse of itself. Since you can not use any API method, key here is to use division operation (/) and remainder operator(%). You can get last digit of a number by %10 e.g. 123%10 will return 3. Similarly you can remove last digit by using /10 e.g. 123/10 will result in 12.