public final class OptionalLong
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A container object which may or may not contain a long value. If a value is present, isPresent() returns true. If no value is present, the object is considered empty and isPresent() returns false.

Additional methods that depend on the presence or absence of a contained value are provided, such as orElse() (returns a default value if no value is present) and ifPresent() (performs an action if a value is present).

This is a value-based class; use of identity-sensitive operations (including reference equality ( ==), identity hash code, or synchronization) on instances of OptionalLong may have unpredictable results and should be avoided.

Since:  1.8

@apiNote OptionalLong is primarily intended for use as a method return type where there is a clear need to represent "no result." A variable whose type is OptionalLong should never itself be null; it should always point to an OptionalLong instance.