OOPS Interview Questions & Answers

1.) Why JAVA is known as securable language?

There are two reasons behind this. The first one is, as JAVA runs in JVM, which is a virtual machine, and it converts source code to byte code, which is not understandable for humans, so its safe. The second reason is JAVA does not support the Pointer concept, hence we can say that JAVA is a securable language.

2.) What is the necessity of Interface?

As java is a Partially Object Oriented language, and it does not support the multiple inheritance concepts, it creates problem for the developers. To over come this situation JAVA provides Interface concept for multiple inheritance.

3.) What is Abstraction?

An essential element of object-oriented programming is abstraction. Abstraction is the process to hide the complexity. A powerful way to manage abstraction is through the use of hierarchical classifications. This allows programmer to understand the semantics of complex system.

4.) What is Polymorphism?

The meaning of Polymorphism is something like one name many forms. Polymorphism enables one entity to be used as general category for different types of actions. The specific action is determined by the exact nature of the situation. The concept of polymorphism can be explained as “one interface, multiple methods”.

5.) What is Inheritance?

Inheritance is the process of basing one class on another. In this process, a base class provides methods, properties, and other members to a derived class. The advantage of inheritance is that you can write and maintain code once it is in the base class and reuse it over and over in the derived classes.

But the main draw back of Java is it doesn’t support multiple Inheritances; hence to over come this draw back Java provides us the Interface concept.

6.) What is Object Oriented Programming Language ?

The language, which obeys all the basic principles of Object Oriented Programming, which are Encapsulation, Inheritance and Polymorphism, is generally known as Object Oriented Programming Language. Languages like c++ and java are some well-known Object Oriented Programming Languages.

7.) What is Encapsulation?

Encapsulation is a process of binding or wrapping the data and the codes that operates on the data into a single entity. This keeps the data safe from outside interface and misuse.

8.) What is Class and Object?

A class defines the abstract characteristics of a thing (object), including the thing’s characteristics, like its attributes or properties and the things it can do.

The code for a class should be relatively self-contained. Collectively, the properties and methods defined by a class are called members. Object a particular instance of a class. Object holds the characteristics of the Class. The set of values of the attributes of a particular object is called its state.

9.) Is JAVA a completely Object Oriented Programming Language?

The answer to this question is certainly no. The reason behind this is JAVA does not obey the OOPs concept purely. Certain concepts like Operator over loading and Multiple Inheritance are not supported by JAVA. Hence JAVA is known as Partially Object Oriented Programming Language.