In this article, we will cover the basic difference between the class method vs Static method in Python and when to use the class method and static method in python. Show The @classmethod decorator is a built-in function decorator that is an expression that gets evaluated after your function is defined. The result of that evaluation shadows your function definition. A class method receives the class as an implicit first argument, just like an instance method receives the instance Syntax Python Class Method: class C(object): @classmethod def fun(cls, arg1, arg2, ...): .... fun: function that needs to be converted into a class method returns: a class method for function.
What is the Static Method in Python?A static method does not receive an implicit first argument. A static method is also a method that is bound to the class and not the object of the class. This method can’t access or modify the class state. It is present in a class because it makes sense for the method to be present in class. Syntax Python Static Method: class C(object): @staticmethod def fun(arg1, arg2, ...): ... returns: a static method for function fun.Class method vs Static MethodThe difference between the Class method and the static method is:
When to use the class or static method?
How to define a class method and a static method?To define a class method in python, we use @classmethod decorator, and to define a static method we use @staticmethod decorator. As explained above we use static methods to create utility functions. In the below example we use a static method to check if a person is an adult or not. Below is the complete Implementation
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In every programming language, memory is a vital resource and is also scarce in nature. Hence it’s essential that the memory is managed thoroughly without any leaks. Allocation and deallocation of memory is a critical task and requires a lot of care and consideration. In this article, we will understand the storage of static methods and static variables in Java. Java Virtual Machine(JVM) is an engine that provides a run time environment to drive the java code. It converts the java byte code into machine language. The JVM has two primary functions. They are:
The JVM memory manager creates memory pools during the runtime of the program. Let’s understand the concept of memory pools in java. There are two types of memory pools namely the stack memory and the heap memory. The main difference between stack memory and the heap memory is that the stack is used to store only the small datatypes whereas heap stores all the instances of the class. And, since java either implicitly or explicitly extends the class from Object.class, every class we create is a collection of objects. This also means that we cannot use a method or a variable unless we instantiate it with a new keyword. As soon as we instantiate the methods, JVM allocates some memory on the heap and it stores the address of the instance on the stack. After this, the methods and variables can be used. In order to get a better understanding of how the new keyword works, let’s take an example. Let’s take a bird class. Whenever a new bird is found, the number of birds need to be incremented. Let’s try to implement this code:
Clearly, this method cannot be used to count the number of birds because at every instance, a new heap is being allocated and for all the instances, the number of birds is being initialized from 0 and is incremented to 1. Therefore, we are creating three independent birds where, in every bird object, the number of birds is 1. In order to avoid this, we initialize the methods and variables as static. This means that the variable or method is not changed for every new object creation. Since these methods and variables cannot be stored in a normal heap, they are stored in a special area called permanent generation(PermGen).
Let’s implement this by changing the number to a static variable.
Note: In Java 5 and 6, PermGen space was used. But due to major changes in memory model in Java 8, storage specification has also been changed. Now a new memory space “MetaSpace” has been introduced where all the names fields of the class, methods of a class with the byte code of methods, constant pool, JIT optimizations are stored. The main reason for this change of PermGen in Java 8.0 is that it is tough to predict the size of PermGen, and it helps in improving garbage collection performance. Article Tags :
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