How to check uppercase and lowercase in Java code example

Example 1: java how to make a string lowercase

/* to find the lowercase or uppercase of a string, 
* we just .toLowerCase() or .toUpperCase()
*/

public class CaseDemonstration {
  public static void main(String[] args) {
    
   	String testString = "THIS IS AN EXAMPLE OF A STRING";
    String testStringLower = testString.toLowerCase(); // make a string lowercase
    System.out.println(testStringLower); // "this is an example of a string"
    String testStringUpper = testStringLower.toUpperCase(); // make it upper again
    System.out.println(testStringUpper); // "THIS IS AN EXAMPLE OF A STRING"
    
  }
}

Example 2: write a program to check whether the character is in lowercase or uppercase in java

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Alphabet_Check {
    public static void main(String args[]) throws IOException{
        char m;
        BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        System.out.print("Enter any alphabet:");
        m = (char) bf.read();
        if(m >= 97 && m <= 123){
            System.out.println("Lower Case");
        }
        else if(m >= 65 && m <= 96){
            System.out.println("Upper Case");
        }
        else if(m >= 48 && m <= 57){
            System.out.println("Digit");
        }
    }
}

Example 3: char to lowercase java

Character.toLowerCasr(<char need to lower>)

Example 4: java lower case to upper case

toUpperCase()