Static Members

Lecture 65:-  Static Members

In Java, static members belong to the class rather than to individual instances (objects) of the class. They are shared among all instances of the class and can be accessed using the class name, without creating an object of the class. Static members are declared with the static keyword.

There are two types of static members in Java:

1. Static Variables (Class Variables): Static variables are shared among all instances of the class. They are initialized only once when the class is loaded into memory and retain their value throughout the program's execution.

   javaCopy code
   public class MyClass {
       // Static variable (class variable)
       static int count = 0;
   
       public MyClass() {
           count++; // Increment count for each instance created
       }
   }
   

2. Static Methods (Class Methods): Static methods are also associated with the class and not with individual instances. They can be called using the class name and do not require an object to be created.

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   public class MathUtility {
       // Static method (class method)
       public static int add(int a, int b) {
           return a + b;
       }
   }
   

Accessing Static Members: Static members can be accessed using the class name or through an instance of the class. However, it is recommended to access static members using the class name to make it clear that the member is shared among all instances.

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// Accessing static variable
int totalCount = MyClass.count;

// Accessing static method
int sum = MathUtility.add(5, 3);

When to Use Static Members:

• Use static variables when you need a value that should be shared among all instances of the class.
• Use static methods when the method does not depend on the state of the instance and does not modify instance-specific variables.
• Utility classes, such as MathUtility in the example above, often have static methods for general-purpose calculations without the need for object instantiation.

Note:

1. Static members cannot directly access non-static (instance) members because they do not belong to any specific instance of the class.
2. Non-static (instance) members can access static members because they belong to the class and are shared among all instances.

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