Java Basics Practice Test:  Java Environment & OOPS Concepts — Flashcards

Quiz on OOPS concepts, JDK, JRE, JIT AND JVM, polymorphism, encapsulation and java buzzwords.

Here are the main OOP concepts in Java:
Encapsulation: Encapsulation is the process of binding data and the code that works on that data together. This prevents accidental changes to the data. In Java, encapsulation is achieved by using classes and objects. A class is a blueprint for creating objects, and an object is an instance of a class. Classes can contain data members (variables) and methods (functions). Data members are used to store data, and methods are used to perform operations on that data. Only the methods of a class can directly access the data members of that class. This helps to protect the data from being accidentally changed.
Abstraction: Abstraction is the process of hiding the implementation details of a class from the user. This allows the user to focus on what the class does, rather than how it does it. In Java, abstraction is achieved by using interfaces. An interface is a blueprint for a class that defines the methods that the class must implement. However, the interface does not specify how the methods are implemented. This allows the user to focus on what the class does, rather than how it does it.
Inheritance: Inheritance is the process of creating a new class from an existing class. The new class inherits the data members and methods of the existing class. This allows the new class to reuse the code of the existing class. In Java, inheritance is achieved using the extends keyword.
Polymorphism: Polymorphism is the ability of an object to take on many forms. In Java, polymorphism is achieved by using method overloading and method overriding.
Method overloading is the ability to have multiple methods with the same name but different parameters. This allows the user to call the same method with different arguments.
Method overriding is the ability to provide a new implementation of a method in a subclass. This allows the subclass to change the behavior of the method.