26_Optional.md

Optional Class

java.util.Optional Class

What is the Optional class?

• The Optional<T> class is a Wrapper class that wraps objects of type 'T', like the Integer or Double classes
  • Therefore, an Optional instance can store reference variables of all types
• Using Optional objects can simplify unexpected NullPointerException
  • That is, exceptions caused by null values can be handled without complex conditional statements

Creating Optional Objects

Optional objects can be created using the of() method or the ofNullable() method

• of() method
  • Returns an Optional object with a specified non-null value
  • If null is stored in an Optional object created through the of() method, a NullPointerException will be thrown
• ofNullable() method
  • If there is a possibility that the reference variable's value could be null, it is better to create an Optional object using the ofNullable() method
  • The ofNullable() method:
    • Returns an Optional object with the specified value if the value is not null,
    • Returns an empty Optional object if the specified value is null