All Flashcards
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 'scope' in programming?
Scope determines where a variable can be used within your code.
Define 'local scope'.
Variables declared inside a method or constructor have local scope; accessible only within that block.
Define 'global scope'.
Variables declared outside any method or constructor have global scope; accessible throughout the class.
What are 'access modifiers'?
Access modifiers control the visibility and accessibility of variables and methods from outside the class.
Define 'private' access modifier.
Private members are only accessible within the class where they are declared.
Define 'package' (default) access.
Accessible by other classes within the same package (folder).
Define 'protected' access.
Accessible by classes in the same package and by subclasses in other packages.
Define 'public' access.
Public members are accessible from any class.
What is an 'instance variable'?
A non-static variable belonging to an object.
Define 'encapsulation'.
Bundling data (variables) and methods that operate on the data into a single unit (class), and hiding the internal details from the outside world.
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).