finalize finalization finally final

finalize

Garbage collector (garbage colector) When you decide to recycle something , Will run the finalize() Method But in Java Unfortunately in China , If there is always enough memory , Then garbage collection may never happen , in other words filalize() May never be implemented , Obviously, it's not reliable to expect it to do the finishing work . that finalize() What is it really about ？ Its main purpose is to recycle the memory applied by special channels .Java The program has a garbage collector , So in general, memory problems don't need programmers to worry about . But there is one kind. JNI(Java Native Interface) call non-Java Program （C or C++）,finalize() My job is to recycle this part of memory

finally

Java Medium Finally The key is generally related to try Use it together , Before the program enters try After block , Whether the program is terminated due to an exception or by other means ,finally The contents of the block must be executed

finally Block of code and finalize() Method difference

Whether or not an exception is thrown ,finally Code blocks will execute , It is mainly used to release the resources occupied by the application .finalize() The method is Object Class protected Method , It is garbage collected by before the object Java Virtual machine to call

final

• final Literally, it means “ final , The final ”. stay Java It's the same meaning in
• final Can be used to modify variables （ Include class properties 、 Object properties 、 Local variables and formal parameters ）、 Method （ Including class methods and object methods ） And the class
• final— Modifier （ keyword ） If a class is declared as final, This means that it can no longer derive new subclasses , Cannot be inherited as a parent class . So a class cannot be declared as abstract Of , It was declared that final Of . Declare a variable or method as final, It can guarantee that they will not be changed in use . Be declared final Must be declared with an initial value , And in the future reference can only read , Do not modify the . Be declared final The same can only be used , Cannot overload