Optionl class

import java.util.Optional;

public class Main {
    public static void main(String[] args) {
      // use only one 1, 2, or 3 as per requirement: 

        // 1. of() -> value must not be null
        Optional<String> op1 = Optional.of("Yogesh");

        // 2. empty() -> no value
        Optional<String> op2 = Optional.empty();

        // 3. ofNullable() -> null allowed
        Optional<String> op3 = Optional.ofNullable(null);

        // -----------------------------------
        // isPresent()
        System.out.println("isPresent: " + op1.isPresent());

        // get()
        System.out.println("get: " + op1.get());

        // orElse()
        System.out.println("orElse: " + op3.orElse("Default Name"));

        // ifPresent()
        op1.ifPresent(name -> System.out.println("ifPresent: " + name));

        // orElseThrow()
        System.out.println("orElseThrow: " + op1.orElseThrow());

        // -----------------------------------
        // empty optional example
        System.out.println("Empty value: " + op2.orElse("No Data"));
    }
}