Core java interview Questions You'll Most Likely Be Asked (Second Edition)

Security: OOPs principles like encapsulation help to keep
the data and the code that operates on the data together and
makes the code secure
Simplicity: Java classes represent real world objects. This
makes code very easy to understand
Maintainability: Code written using OOPs principles is
easier to maintain
Write a code snippet that demonstrates encapsulation.
Answer:
Encapsulation refers to keeping the data and the code that
operates on the data together as a single unit. Simply creating a
class with private fields and public getter/setter methods is an

---

004.
a.
b.
example of encapsulation. The following code snippet
demonstrates this:
public class Laptop {
private String memory;
public String getMemory () {
return memory;
}
public String setMemory (String newMemory){
memory = newMemory;
}
}
Here, there is a class called Laptop. It has a private field called
memory and public getter and setter methods to access/modify
the memory field. So, the memory field cannot be accessed
directly outside the class, it can only be accessed via its
getter/setter methods.
What are the types of inheritance relationships?
Answer:
Inheritance relationships specify how code can be reused. There
are two types of inheritance relationships.
They are as follows:
IS–A
An IS–A relationship is implemented via inheritance, that is by
creating a sub–class. Assume that, Camera is a subclass and
Electronics is a super class. In that case, we can say that,
Camera IS–A Electronic product
HAS–A

---

005.
006.
A HAS–A relation can be created via composition, that is by
creating a field corresponding to another class. Assume that,
inside the Camera class, there is an object called Battery. In
that case, we can say that Camera HAS–A object called
Battery