Java Programming - Classes and Access Specifiers

What is the scope of the private access specifier in Java?

Which access specifier is used to allow visibility only within a package?

What concept in Java is used to bind data and methods together?

What type of polymorphism is achieved through method overloading?

In Java, which keyword is used to prevent runtime polymorphism?

What is the purpose of a helper class in Java?

What does the qualified name of a class include?

Which of the following is NOT a type of access specifier in Java?

Which access specifier allows visibility within a class and its subclasses only?

What is the main characteristic of runtime polymorphism?

Which keyword is used in Java to define a method that cannot be overridden to prevent runtime polymorphism?

Which access specifier can be applied without an explicit keyword?

What does encapsulation in Java primarily achieve?

Compile time polymorphism is also known by which of the following terms?

What is the primary role of a helper class in Java?

Which keyword is used to make a variable or method accessible throughout different packages?

Package Classes

To compile package classes, use the command javac -d FileName.java. This saves the compiled class files to the specified directory.
To use classes from other packages, use the package keyword with the qualified name (package + class name). Example: a.b.c.d.e.Demo.

Access Specifiers

Access specifiers control the visibility of classes or elements within a class.
Types of access specifiers:
- private: Accessible only within the class.
- default: Accessible within the same package. No keyword needed, it's implicit.
- protected: Accessible within the package and by subclasses, even if in different packages.
- public: Accessible throughout the program.

Encapsulation

Encapsulation hides data inside a class.
Also known as data binding or wrapping of a class.

Interfaces and Abstract Classes

Interfaces: Used for multiple inheritance, as blueprints, achieving loosely coupled code, and strong abstraction.
Abstract classes: Used for achieving abstraction.

Helper Classes

Helper classes provide functions to assist the main program.
To avoid redundant code implementation.

Polymorphism

Polymorphism allows code execution with different behaviors.
Enables code to adapt to requirements.

Types of Polymorphism

Compile-time (early/static binding):
- Achieved through method overloading.
- Executes methods based on parameters.
- Useful for end-users
- Unpreventable
Runtime (late/dynamic binding):
- Achieved through method overriding.
- Executes methods based on the object type.
- Useful for developers
- Preventable using the final keyword.

This quiz covers key concepts in Java programming, specifically focusing on package classes, access specifiers, encapsulation, interfaces, and abstract classes. Test your understanding of these fundamental Java principles and how they interact to create robust applications.