String Manipulation

Check next char alphabet

/**
* this is to check letter alphabet:
*/

char chr = 'b';
chr = (char) (chr + 4);
System.out.println(chr);
--output--> f

note: but this way is not suitable if the next letter is more than z. 

/** other way */

check String Match Patter

/**
* check String ony contain a-z or A-z 
* not allow other character
*/

String s1 = "xxxx";
return !s1.matches("[a-zA-Z]+");

/** other check way using Class Pattern */
Pattern p = Pattern.compile("[^a-zA-Z]");
return p.matcher(s1).find();

/** if only check a String contain non aphabets, it can use class Character */
private static boolean checkChar(String s){
  boolean result = false;
    for (int i = 0; i < s.length(); i++) {
        char charAt2 = s.charAt(i);
        result = Character.isLetter(charAt2);
    }
    return result;
}


/** check length unmatch pattern of a String */
String s = "valueString";
return s.replaceAll("[a-m]", "").length();

Convert String to ASCII Value

/**
* count sum of ASCII in String
*/
String s1="SampleofString"
int lengthS1 = 0;
for(char ch1 : s1.toUpperCase().toCharArray()){
  lengthS1 += (int)ch1;
}
return lengthS1;

/** other way using java 8 */
String s1="valueString";
return s1.toUpperCase().chars().sum();

sorting a random number to descending

private static int sorting(int num){
  /** using java 8 */
   return Integer.parseInt(String.valueOf(num)
               .chars()
               .mapToObj(i -> String.valueOf(Character.getNumericValue(i)))
               .sorted(Comparator.reverseOrder())
               .collect(Collectors.joining()));

  /** using stringBuilder java 8 */ 
  if (num < 0) throw new IllegalArgumentException("Negative number: " + num);

      return Integer.parseInt(Integer.toString(num).codePoints()
              .sorted()
              .collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append)
              .reverse()
              .toString()); 

  /** using normal way */ 
  String[] numbers = (Integer.toString(Integer.valueOf(num))).split("");
    Arrays.sort(numbers);

    String result = "";

    for(String s : numbers)
    {
      result = s + result;
    }

    return Integer.parseInt(result);

    /** using String join */
    String[] array = String.valueOf(num).split("");
      Arrays.sort(array, Collections.reverseOrder());
      return Integer.valueOf(String.join("", array));   
}