Quick Answer: Why Factory Method Is Static?

Can we override static method?

Can we override a static method.

No, we cannot override static methods because method overriding is based on dynamic binding at runtime and the static methods are bonded using static binding at compile time.

So, we cannot override static methods..

What is difference between final and static?

static means there is only one copy of the variable in memory shared by all instances of the class. The final keyword just means the value can’t be changed. Without final , any object can change the value of the variable.

Can static be final?

Static variable: When the value of a variable is not varied, then it is a not good choice to go for instance variable. … Declaring variables only as static can lead to change in their values by one or more instances of a class in which it is declared. Declaring them as static final will help you to create a CONSTANT.

Can we override main method?

No, we cannot override main method of java because a static method cannot be overridden. The static method in java is associated with class whereas the non-static method is associated with an object. … Therefore, it is not possible to override the main method in java.

Why are static methods bad?

In the universe of OO static methods are anti-matter. They don’t have to be bad, but they are dangerous, because they are used incorrectly. There are only two situations when static methods or variables are being used and it’s not an abomination. Declaring a true global constant, not a global variable.

Should a factory be static?

No, factory class by default shouldn’t be static. Actually, static classes are not welcomed in OOP world since they can also convey some state and therefore introduce global application state. If you need only one factory object to be present, you can control it’s creation through singleton pattern.

What is the static?

adjective Also stat·i·cal . pertaining to or characterized by a fixed or stationary condition. showing little or no change: a static concept; a static relationship. lacking movement, development, or vitality: The novel was marred by static characterizations, especially in its central figures.

Can we write static block in main method?

Executing a static block JVM first looks for the main method (at least the latest versions) and then, starts executing the program including static block. Therefore, you cannot execute a static block without main method.

What is the purpose of static?

In Java, static keyword is mainly used for memory management. It can be used with variables, methods, blocks and nested classes. It is a keyword which is used to share the same variable or method of a given class. Basically, static is used for a constant variable or a method that is same for every instance of a class.

Can a class be static?

So, Yes, you can declare a class static in Java, provided the class is inside a top-level class. Such clauses are also known as nested classes and they can be declared static, but if you are thinking to make a top-level class static in Java, then it’s not allowed.

What is static in Java?

In the Java programming language, the keyword static indicates that the particular member belongs to a type itself, rather than to an instance of that type. This means that only one instance of that static member is created which is shared across all instances of the class.

Can constructor be static?

No, we cannot define a static constructor in Java, If we are trying to define a constructor with the static keyword a compile-time error will occur. In general, static means class level. … We need to assign initial values for an instance variable we can use a constructor.

When should I make a method static?

You should use static methods whenever,The code in the method is not dependent on instance creation and is not using any instance variable.A particular piece of code is to be shared by all the instance methods.The definition of the method should not be changed or overridden.More items…•

Is static class bad?

Certainly there is a time when too many static functions are a sign of something gone wrong, but, within reason, it is not ‘bad’. Static functions are more efficient than non-static because you don’t need to create an instance of an object to use them or pass a ‘this’ pointer into method calls.

Is static method thread safe?

6 Answers. It is well known that static methods with immutable objects as parameters are thread safe and mutable objects are not. … The method you posted is thread-safe. It maintains no state and operates only on its arguments.

Can we override private method?

No, we cannot override private or static methods in Java. Private methods in Java are not visible to any other class which limits their scope to the class in which they are declared.

What is static factory method?

A static factory method is a public static method on the object that returns a new instance of the object. These type of methods share the same benefits as the traditional factory method design pattern. This is especially useful for value objects that don’t have a separate interface and implementation class.

Can we create object in Static Block?

You can use it to initialize a class or to do some logic during class load. If you remove the static modifier the code block is an instance initializer. For instance, with static initializers you can initialize a map with db data to be used later during object instantiation.

How do you name a factory method?

Factory method doesn’t dictate on method name. You can have as many methods you want in your factory, provided all of them return the object from same family.

Can we inherit static method in Java?

Static methods in Java are inherited, but can not be overridden. If you declare the same method in a subclass, you hide the superclass method instead of overriding it. Static methods are not polymorphic. At the compile time, the static method will be statically linked.

Can we define static block inside a method?

Static block always get executed before static method. … The this and super keywords cannot be used inside the static block. If a class have multiple blocks then they will execute in the same order as they written.

Which method Cannot be overridden?

A method declared final cannot be overridden. A method declared static cannot be overridden but can be re-declared. If a method cannot be inherited, then it cannot be overridden. A subclass within the same package as the instance’s superclass can override any superclass method that is not declared private or final.

What are the advantages of static factory methods?

Another advantage of static factories is that, unlike constructors, they are not required to return a new object every time they are invoked. This is extremely useful when working with immutable classes to provide constant objects for common used values and avoid creating unnecessary duplicate objects. The Boolean.

What is factory function C++?

A factory method is a static method of a class that returns an object of that class’ type. But unlike a constructor, the actual object it returns might be an instance of a subclass. Another advantage of a factory method is that it can return existing instances multiple times.