(1) Final: modifiers can be used to modify variables, methods, and classes. Variables modified by final can only be assigned once; Methods modified by final cannot be overridden in subclasses; Classes modified by final cannot be inherited.
(2) Finally is used in exception handling to define that the code in the finally block is always executed, regardless of whether the code in the try block throws an exception and whether the catch matches, unless the JVM is shut down (system.exit (1)). Usually used to free external resources (resources that are not collected by the garbage collector).
The (3) Finalize () method is a method defined in the Object class, and the Finalize () method of the Object is called when the garbage collector clears the garbage Object from memory. Because the method is protected, subclasses can override the method to defragment resources or perform other cleanup tasks.