Java Data Type How to - Check if character is a digit, letter, white space, lower case or upper case character

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Question

We would like to know how to check if character is a digit, letter, white space, lower case or upper case character.

Answer

/*from  ww w .j ava 2s .  c  om*/
public class Main {

  public static void main(String[] args) {

    char a[] = { 'a', 'b', '5', '?', 'A', ' ' };

    for (int i = 0; i < a.length; i++) {

      if (Character.isDigit(a[i]))
        System.out.println(a[i] + "is a digit ");
      if (Character.isLetter(a[i]))
        System.out.println(a[i] + "is a letter ");
      if (Character.isWhitespace(a[i]))
        System.out.println(a[i] + "is a White Space ");
      if (Character.isLowerCase(a[i]))
        System.out.println(a[i] + "is a lower case ");
      if (Character.isLowerCase(a[i]))
        System.out.println(a[i] + "is a upper case ");
    }

  }
}

The code above generates the following result.

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