[java] Checking if a character is a special character in Java

Take a look at class java.lang.Character static member methods (isDigit, isLetter, isLowerCase, ...)

Example:

String str = "Hello World 123 !!";
int specials = 0, digits = 0, letters = 0, spaces = 0;
for (int i = 0; i < str.length(); ++i) {
   char ch = str.charAt(i);
   if (!Character.isDigit(ch) && !Character.isLetter(ch) && !Character.isSpace(ch)) {
      ++specials;
   } else if (Character.isDigit(ch)) {
      ++digits;
   } else if (Character.isSpace(ch)) {
      ++spaces;
   } else {
      ++letters;
   }
}