What are the uses of final?

final It's also a place that many interviews like to ask , But I think it's boring , Usually can answer the following 5 It's good to order :

By final Decorated classes cannot be inherited

By final The decorated method cannot be overridden

By final Modified variables cannot be changed . If embellishment references , That means that the reference is immutable , The reference points to a variable content .

By final The method of decoration ,JVM Will try to inline it , To improve operational efficiency

By final Constant decorated , In the compilation phase, it will be stored in the constant pool .

besides , The compiler to final The two reordering rules that domains follow are better :

I have one in the constructor final The changes to the domain , And then assign the reference of the constructed object to a reference variable , Between these two operations

Cannot reorder Read an include for the first time final A reference to an object of a domain , And then read this for the first time final Domain , There is no reordering between the two operations .