static-methods

I'm confused why the following is not allowed: public interface MyInterface { MyInterface getInstance(String name); } public class MyImplementation implements MyInterface { public MyImplementation(String name) { } @Override public static MyInterface getInstance(String name) { // static is not allowed here return new MyImplementation(name) } } I understand why a method in the interface cannot be static, but why can't the overriding method be? I want all classes to implement the getInstance(String name) method, but I'm currently limited to only being able to call the method if the object has

I am interested whether should I manually inline small methods which are called 100k - 1 million times in some performance-sensitive algorithm. First, I thought that, by not inlining, I am incurring some overhead since JVM will have to find determine whether or not to inline this method (or even fail to do so). However, the other day, I replaced this manually inlined code with invocation of static methods and seen a performance boost. How is that possible? Does this suggest that there is actually no overhead and that by letting JVM inline at "its will" actually boosts performance? Or this

When and how are static methods suppose to be used in python? We have already established using a class method as factory method to create an instance of an object should be avoided when possible. In other words, it is not best practice to use class methods as an alternate constructor (See Factory method for python object - best practice ). Lets say I have a class used to represent some entity data in a database. Imagine the data is a dict object containing field names and field values and one of the fields is an ID number that makes the data unique. class Entity(object): def __init__(self,

We have two classifications heap and stack . When a object is created, memory for object is stored in heap. What if the class has static methods ,which can be called using class name. If object is not created then how will it allocate memory and if it does where will it allocate memory? It depends on the JVM, but static fields are usually stored in a special object on the heap. (You can see it in a heap dump) When the ClassLoader is unloaded, its classes and their static "objects"/fields are also cleaned up. The only thing different about the static "object" is you can't get a reference to it.

Why in PHP you can access static method via instance of some class but not only via type name? UPDATE: I'm .net developer but i work with php developers too. Recently i've found this moment about static methods called from instance and can't understand why it can be usefull. EXAMPLE: class Foo { public static Bar() { } } We can accept method like this: var $foo = new Foo(); $foo.Bar(); // ?????? Ibrahim Azhar Armar In PHP the class is instantiated using the new keyword for example; $MyClass = new MyClass(); and the static method or properties can be accessed by using either scope resolution

I'm asking because I'm trying to use a mocking framework (Mockito) which does not allow you to mock static methods. Looking into it I've found quite a few blog posts saying that you should have as few static methods as possible, but I'm having difficulty wrapping my head around why. Specifically why methods that don't modify the global state and are basically helper methods. For instance I have a class called ApiCaller that has several static methods. One of the static method's purpose is to execute an HTTP call, deal with any custom issues our server might have returned (ex. user not logged

This question already has an answer here: calling non-static method in static method in Java [duplicate] 14 answers I have class foo{ public static void main(String[] args){ do(); } public void do(){} } but then when I call do() from main by running the command java foo on the command line, java complains that you can't call a method from a static function. So my question is: How do you call methods from the main method and if it is not possible what are some alternative strategies to call methods after the program is run from the command line using the java command. You can only call instance

Imagine there is a Customer class with an instance Load() method. When the Load() method is called, it retrieves order details by e.g. var orders = Order.GetAll(customerId, ...); GetAll() is a static method of the Order class and the input parameters are fields defined in the Customer class. As you can see, Order is a dependency of the Customer class, however, I can't just create an IOrder and inject it there as interfaces can't have static methods. Therefore, the question is how could I introduce dependency injection in this example? I don't want to make GetAll() an instance method since it's

Does anyone have any good examples of using static methods instead of dynamic? Singleton: class SingletonClass { private static $instance; private function __construct() { } public function __clone() { trigger_error('Clone is not allowed.', E_USER_ERROR); } public static function init() { if (!isset(self::$instance)) { $c = __CLASS__; self::$instance = new $c; } return self::$instance; } // other public, dynamic methods for singleton } $singleton = SingletonClass::init(); Track number of instances: class CountMe { public static $instances = 0; public function __construct() { CountMe::