Optional class in Java

    Optional class is a public final class and used to deal with NullPointerException in Java application. You must import java.util package to use this class. It provides methods which are used to check the presence of value for particular variable.

import java.util.Optional;

public class OptionalExample {

public static void main(String[] args) {

Optional<String> optionalName = Optional.of("John");

// Check if a value is present

if (optionalName.isPresent()) {

System.out.println("Name is present: " + optionalName.get());

}

// Providing a default value if the optional is empty

String name = optionalName.orElse("Default Name");

System.out.println("Name or default: " + name);

// Handling the case when a value is absent

Optional<String> emptyOptional = Optional.empty();

String defaultName = emptyOptional.orElse("Default Name");

System.out.println("Default name from empty optional: " + defaultName);

// Throwing an exception if a value is absent

try {

String nameOrThrow = emptyOptional.orElseThrow(IllegalStateException::new);

System.out.println("Name or throw: " + nameOrThrow);

} catch (IllegalStateException e) {

System.out.println("Caught IllegalStateException: " + e.getMessage());

}

}

}