finalize() method in java 


protected void finalize() throws Throwable {}
  • every class inherits the finalize() method from java.lang.Object
  • the method is called by the garbage collector when it determines no more references to the object exist
  • the Object finalize method performs no actions but it may be overridden by any class
  • normally it should be overridden to clean-up non-Java resources ie closing a file
  • if overridding finalize() it is good programming practice to use a try-catch-finally statement and to always call super.finalize(). This is a safety measure to ensure you do not inadvertently miss closing a resource used by the objects calling class
    protected void finalize() throws Throwable {
     try {
         close();        // close open files
     } finally {
         super.finalize();
     }
 }
  • any exception thrown by finalize() during garbage collection halts the finalization but is otherwise ignored
  • finalize() is never run more than once on any object

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