All Flashcards
What are the key differences between private and public access modifiers?
Private: accessible only within the class. Public: accessible from any class.
Compare local and global variables in terms of scope.
Local: limited to the block they are defined in. Global: accessible throughout the class.
What are the differences between 'package' and 'protected' access modifiers?
Package: accessible within the same package. Protected: accessible within the same package and by subclasses in other packages.
Contrast the use cases of public instance variables vs. private instance variables with public getter/setter methods.
Public instance variables: simpler but violate encapsulation. Private with getters/setters: more complex but allows controlled access and modification.
Compare the scope of static vs. instance variables.
Static: class-level scope, shared by all instances. Instance: object-level scope, unique to each instance.
Differentiate between access modifiers and scope.
Access modifiers: control visibility from outside the class. Scope: determines where a variable is accessible within the code.
Compare the accessibility of a variable declared without any access modifier versus one declared as public.
No modifier (package-private): accessible only within the same package. public: accessible from anywhere.
Contrast the impact of using private vs. protected members in the context of inheritance.
private: not accessible to subclasses. protected: accessible to subclasses, allowing for controlled inheritance.
Compare the use of local variables inside a method versus parameters passed to the method.
Local variables: declared and initialized within the method. Parameters: passed into the method from the caller.
Contrast the scope of a variable declared inside an 'if' statement block versus a variable declared outside the 'if' statement but within the same method.
Inside 'if': scope limited to the 'if' block. Outside 'if': scope extends to the entire method (excluding shadowed regions).
How is encapsulation achieved using access modifiers?
By declaring instance variables as private and providing public getter and setter methods.
Give an example of when to use a private static variable.
For constants or counters that should only be accessed and modified within the class.
How do access modifiers support information hiding?
By restricting access to internal data and implementation details, preventing external classes from directly manipulating them.
In what scenario would you use the 'protected' access modifier?
When you want to allow subclasses in other packages to access a member but prevent access from non-related classes.
How can proper use of scope prevent naming conflicts?
By limiting the visibility of variables, reducing the chance of accidentally using the same name for different variables in different parts of the code.
How does the concept of scope apply to method parameters?
Method parameters have local scope within the method, allowing the method to operate on specific inputs without affecting variables outside the method.
Explain how access modifiers contribute to creating a stable and maintainable API.
By defining a clear interface with public members and hiding implementation details with private members, changes to the internal implementation do not affect external code that uses the API.
How can access modifiers and scope be used to implement a singleton pattern?
By making the constructor private and providing a public static method to access the single instance, controlling instantiation and access.
How can access modifiers be used to create immutable objects?
By declaring all instance variables as private and not providing any setter methods, preventing modification of the object's state after creation.
How does the use of access modifiers and scope contribute to code reusability?
By creating well-defined interfaces and encapsulating implementation details, classes can be reused in different contexts without unintended side effects or dependencies.
What is the significance of local scope?
It limits variable access, preventing unintended modifications and promoting modularity.
What is the significance of global scope?
It allows variables to be accessed from anywhere in the class, but can increase the risk of unintended side effects.
Why are instance variables often declared private?
To encapsulate data and control access to the object's state.
What is the purpose of access modifiers in object-oriented programming?
To control the visibility and accessibility of class members, enforcing encapsulation and abstraction.
Explain the concept of data hiding.
Restricting access to the internal representation of an object, preventing direct manipulation from outside the class.
What happens when a local variable has the same name as a global variable?
The local variable takes precedence within its scope, shadowing the global variable.
How does inheritance relate to the 'protected' access modifier?
Protected members are accessible by subclasses, enabling inheritance while still providing some level of encapsulation.
What is the role of the 'public' access modifier in class design?
It defines the interface of the class, specifying which methods and constructors are accessible from other classes.
Why is understanding scope important for debugging?
Knowing the scope of variables helps identify where a variable's value might be unexpectedly changed or accessed.
How do static variables relate to scope and access?
Static variables have class-level scope and are shared by all instances of the class. Their access is controlled by access modifiers.