Optional Class in Java
======================
What is an Optional Class?
The Optional class in Java is a container object that may or may not contain a non-null value. It is used to avoid null pointer exceptions by providing a way to handle null values more effectively.
Available Methods in Optional Class
Optional.isPresent() – Checks if a value is present in the Optional.
Optional.get() – Gets the value from the Optional if present, otherwise throws NoSuchElementException.
Optional.orElse(T other) – Returns the value if present, otherwise returns the specified other value.
Optional.orElseGet(Supplier other) – Returns the value if present, otherwise returns the result produced by the supplying function.
Optional.orElseThrow(Supplier exceptionSupplier) – Returns the value if present, otherwise throws the exception produced by the supplying function.
Optional.ifPresent(Consumer consumer) – Executes the specified consumer if a value is present.
Optional.filter(Predicate predicate) – Filters the value of the Optional if present based on the specified predicate.
Optional.map(Function mapper) – Maps the value of the Optional if present using the specified mapper function.
Optional.flatMap(Function> mapper) – Maps the value of the Optional if present to another Optional using the specified mapper function.
Example
public class OptionalExample {
public static void main(String[] args) {
// Example of Optional.isPresent()
Optional<String> optionalString = Optional.ofNullable(“Hello”);
System.out.println(“Is value present? ” + optionalString.isPresent());
// Example of Optional.get()
String value = optionalString.get();
System.out.println(“Value: ” + value);
// Example of Optional.orElse()
Optional<String> emptyOptional = Optional.empty();
String result = emptyOptional.orElse(“Default Value”);
System.out.println(“Result: ” + result);
// Example of Optional.ifPresent()
optionalString.ifPresent(val -> System.out.println(“Value is present: ” + val));
// Example of Optional.map()
Optional<Integer> optionalLength = optionalString.map(String::length);
optionalLength.ifPresent(len -> System.out.println(“Length of value: ” + len));
}
}
Conclusion
The Optional class in Java provides a set of methods to handle null values effectively, reducing the chances of null pointer exceptions and improving code readability.
