Program that moves characters in n steps to the next character in alphabet based on ASCII code
You should try to state your problem more clearly: "the program that moves the character to the next character" seem to assume we know some other program you're referring to. If I understand what you're trying to do, this is the problem:

"Given a String, replace each alphabetical character with the character STEP positions after in the alphabet, wrapping around if needed." 

If this is the problem you're trying to solve, here is how I would do it:

public static char nextCharacterInAlphabet(char character , int step) {
  boolean isLower = Character.isLowerCase(character);
  char c = Character.toLowerCase(character);
  if (c &lt; 'a' || c &gt; 'z')
    return character;
  char nextC = (char)((c - 'a' + step) % 26 + 'a');
  return isLower ? nextC : Character.toUpperCase(nextC);
}