java.util.Optional<T>
, java.util.OptionalDouble
, java.util.OptionalInt
,
java.util.OptionalLong
, or com.google.common.base.Optional
are used as types for fields or parameters.
Optional
was designed to provide a limited mechanism for library method return types in which a clear way to represent "no result"
was needed.
Using a field with the java.util.Optional
type is also problematic if the class needs to be
Serializable
, as java.util.Optional
is not serializable.
Example:
class MyClass {
Optional<String> name; // Optional field
// Optional parameter
void setName(Optional<String> name) {
this.name = name;
}
}
New in 2016.1