java.lang.Character.isLetter(char ch) java.lang.Character.isJavaIdentifierStart(int codePoint) java.lang.Character.isLetter(int codePoint) java.lang.Character.isLetter(char ch) package com.codingdict; import java.lang.*; public class CharacterDemo { public static void main(String[] args) { // create 2 char primitives ch1, ch2 char ch1, ch2; // assign values to ch1, ch2 ch1 = 'A'; ch2 = '9'; // create 2 boolean primitives b1, b2 boolean b1, b2; // check if ch1, ch2 are letter or not and assign results to b1, b2 b1 = Character.isLetter(ch1); b2 = Character.isLetter(ch2); String str1 = ch1 + " is a letter is " + b1; String str2 = ch2 + " is a letter is " + b2; // print b1, b2 values System.out.println( str1 ); System.out.println( str2 ); } } java.lang.Character.isJavaIdentifierStart(int codePoint) java.lang.Character.isLetter(int codePoint)