“private static” Variable in Java

 A private static variable in Java combines the characteristics of both private and static keywords.

• private: 

  This access modifier restricts the visibility of the variable, making it accessible only within the class where it is declared. No other class, not even subclasses or classes in the same package, can directly access a private variable.
• static: 

  This keyword indicates that the variable belongs to the class itself, rather than to any specific instance (object) of the class. All instances of the class share the same single copy of the static variable. It is initialized once when the class is loaded into memory. 

Key characteristics of private static variables:

• Class-level scope: 

  They are associated with the class, not with individual objects.
• Shared across instances: 

  All objects of the class share the same value of the private static variable.
• Encapsulation: 

  Their private access modifier enforces encapsulation, meaning their internal state is protected and can only be modified or accessed through methods provided by the class (e.g., public static getter/setter methods).
• Memory allocation: 

  They are allocated memory only once when the class is loaded, typically in the method area (or Metaspace in Java 8 and later).

Common uses for private static variables:

• Constants: When declared with final as well, they represent constants that are used internally within the class and cannot be changed after initialization.

Java

    class MyClass {
        private static final int MAX_VALUE = 100;
        // ...
    }

• Utility counters or flags: Maintaining a count of instances or a shared flag that affects the behavior of the class as a whole.

Java

    class GlobalCounter {
        private static int count = 0;

        public GlobalCounter() {
            count++;
        }

        public static int getCount() {
            return count;
        }
    }

• Shared resources or configuration: Storing data or resources that need to be accessible to all instances of the class but should not be directly exposed to external classes.

References Used :- Google AI Review