Optional
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[{“Name”:“Java SE 8”,“GroupName”:null},{“Name”:“Java SE 9 (Early Access)”,“GroupName”:null}]
Introduction
Optional
is a container object which may or may not contain a non-null value. If a value is present, isPresent()
will return true
and get()
will return the value.
Additional methods that depend on the presence of the contained value are provided, such as orElse()
, which returns a default value if value not present, and ifPresent()
which executes a block of code if the value is present.
Syntax
- Optional.empty() // Creates an empty Optional instance.
- Optional.of(value) // Returns an Optional with the specified non-null value. A NullPointerException will be thrown if the passed value is null.
- Optional.ofNullable(value) // Returns an Optional with the specified value that may be null.
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