Java/Java Testing/C++ UPDATED ACTUAL
Exam Questions and CORRECT Answers
What is JAVA - CORRECT ANSWER - A high-level programming language developed by
Sun Microsystems. Java was originally called OAK, and was designed for handheld devices and
set-top boxes. Oak was unsuccessful so in 1995 Sun changed the name to Java and modified the
language to take advantage of the burgeoning World Wide Web.
What are the basic concepts of object oriented programming? - CORRECT ANSWER -
Object-oriented programming (OOP) is a programming language model organized around
objects rather than "actions" and data rather than logic.
Historically, a program has been viewed as a logical procedure that takes input data, processes it,
and produces output data. The programming challenge was seen as how to write the logic, not
how to define the data.
Object-oriented programming takes the view that what we really care about are the objects we
want to manipulate rather than the logic required to manipulate them.
What is encapsulation? - CORRECT ANSWER - The wrapping up of data and functions
into a single unit (called class) is known as encapsulation.
Encapsulation containing and hiding information about an object, such as internal data structures
and code.
Define inheritance? - CORRECT ANSWER - Inheritance is the process by which objects
of one class acquire properties of objects of another class.
It allows the extension and reuse of existing code without having to rewrite the code from
scratch.
,Define polymorphism? - CORRECT ANSWER - Polymorphism simply means "many
forms". In java polymorphism is acheived through method overloading and overriding.
For example, say you have an Animal class and two sub classes called Lion and Cat class. All
animals make a sound, so lets say there is a make sound method in all of these classes.
When you call the make sound method from a lion object that is stored in an Animal reference, it
would call the make sound method from the Lion Class. That is how you would explain
polymorphism using overriding.
Define Constructors? - CORRECT ANSWER - A constructor is a member method with the
same name as its class. The constructor is invoked whenever an object of its associated class is
created.It is called constructor because it constructs the values of data members of the class.
What is a Class? - CORRECT ANSWER - A class is a blueprint for an object
What is an Object? - CORRECT ANSWER - An instance of a class
What is multiple inheritance? - CORRECT ANSWER - A class can inherit properties from
more than one class which is known as multiple inheritance.
What are the advantages of inheritance? - CORRECT ANSWER - Code reusability
Saves time in program development.
What is the difference between an Array and a List? - CORRECT ANSWER - The main
difference between an array and a list is how they internally store the data. whereas Array is
collection of homogeneous elements. List is collection of heterogeneous elements.
What is an iterator? - CORRECT ANSWER - Iterators are like pointers. They are used to
access the elements of containers thus providing a link between algorithms and containers.
Iterators are defined for specific containers and used as arguments to algorithms.
, What is this pointer? - CORRECT ANSWER - It is a pointer that points to the current
object. This can be used to access the members of the current object with the help of the arrow
operator.
What are pass by reference and passby value? - CORRECT ANSWER - Pass By
Reference means the passing the address itself rather than passing the value.
Passby Value means passing a copy of the value to be passed.
What is the Java API? - CORRECT ANSWER - What is the Java API?
The Java API is a large collection of ready-made software components that provide many useful
capabilities, such as graphical user interface (GUI) widgets.
What is the Java Virtual Machine (JVM)? - CORRECT ANSWER - The Java Virtual
Machine is software that can be ported onto various hardware-based platforms.
What is variables and then types - CORRECT ANSWER - Variables is an identifier that
denotes a storage location used to store a data values.unlike constants that remain unchanged
during the execution of a program, a variable may takes different values at different times during
the execution of the program.
Instance variables
Class variables
***Class variables only have one copy that is shared by all the different objects of a class,
whereas every object has it's own personal copy of an instance variable**
Local variable
Parameters
what is dot operator? - CORRECT ANSWER - The dot operator(.) is used to access the
instance variables and methods of class objects.It is also used to access classes and sub-packages
from a package.
Examples :
Exam Questions and CORRECT Answers
What is JAVA - CORRECT ANSWER - A high-level programming language developed by
Sun Microsystems. Java was originally called OAK, and was designed for handheld devices and
set-top boxes. Oak was unsuccessful so in 1995 Sun changed the name to Java and modified the
language to take advantage of the burgeoning World Wide Web.
What are the basic concepts of object oriented programming? - CORRECT ANSWER -
Object-oriented programming (OOP) is a programming language model organized around
objects rather than "actions" and data rather than logic.
Historically, a program has been viewed as a logical procedure that takes input data, processes it,
and produces output data. The programming challenge was seen as how to write the logic, not
how to define the data.
Object-oriented programming takes the view that what we really care about are the objects we
want to manipulate rather than the logic required to manipulate them.
What is encapsulation? - CORRECT ANSWER - The wrapping up of data and functions
into a single unit (called class) is known as encapsulation.
Encapsulation containing and hiding information about an object, such as internal data structures
and code.
Define inheritance? - CORRECT ANSWER - Inheritance is the process by which objects
of one class acquire properties of objects of another class.
It allows the extension and reuse of existing code without having to rewrite the code from
scratch.
,Define polymorphism? - CORRECT ANSWER - Polymorphism simply means "many
forms". In java polymorphism is acheived through method overloading and overriding.
For example, say you have an Animal class and two sub classes called Lion and Cat class. All
animals make a sound, so lets say there is a make sound method in all of these classes.
When you call the make sound method from a lion object that is stored in an Animal reference, it
would call the make sound method from the Lion Class. That is how you would explain
polymorphism using overriding.
Define Constructors? - CORRECT ANSWER - A constructor is a member method with the
same name as its class. The constructor is invoked whenever an object of its associated class is
created.It is called constructor because it constructs the values of data members of the class.
What is a Class? - CORRECT ANSWER - A class is a blueprint for an object
What is an Object? - CORRECT ANSWER - An instance of a class
What is multiple inheritance? - CORRECT ANSWER - A class can inherit properties from
more than one class which is known as multiple inheritance.
What are the advantages of inheritance? - CORRECT ANSWER - Code reusability
Saves time in program development.
What is the difference between an Array and a List? - CORRECT ANSWER - The main
difference between an array and a list is how they internally store the data. whereas Array is
collection of homogeneous elements. List is collection of heterogeneous elements.
What is an iterator? - CORRECT ANSWER - Iterators are like pointers. They are used to
access the elements of containers thus providing a link between algorithms and containers.
Iterators are defined for specific containers and used as arguments to algorithms.
, What is this pointer? - CORRECT ANSWER - It is a pointer that points to the current
object. This can be used to access the members of the current object with the help of the arrow
operator.
What are pass by reference and passby value? - CORRECT ANSWER - Pass By
Reference means the passing the address itself rather than passing the value.
Passby Value means passing a copy of the value to be passed.
What is the Java API? - CORRECT ANSWER - What is the Java API?
The Java API is a large collection of ready-made software components that provide many useful
capabilities, such as graphical user interface (GUI) widgets.
What is the Java Virtual Machine (JVM)? - CORRECT ANSWER - The Java Virtual
Machine is software that can be ported onto various hardware-based platforms.
What is variables and then types - CORRECT ANSWER - Variables is an identifier that
denotes a storage location used to store a data values.unlike constants that remain unchanged
during the execution of a program, a variable may takes different values at different times during
the execution of the program.
Instance variables
Class variables
***Class variables only have one copy that is shared by all the different objects of a class,
whereas every object has it's own personal copy of an instance variable**
Local variable
Parameters
what is dot operator? - CORRECT ANSWER - The dot operator(.) is used to access the
instance variables and methods of class objects.It is also used to access classes and sub-packages
from a package.
Examples :
