Java Classes Interview Questions & Answers Download PDF
Prepare comprehensively for your Java Classes interview with our extensive list of 76 questions. Each question is designed to test and expand your Java Classes expertise. Suitable for all experience levels, these questions will help you prepare thoroughly. Secure the free PDF to access all 76 questions and guarantee your preparation for your Java Classes interview. This guide is crucial for enhancing your readiness and self-assurance.
76 Java Classes Questions and Answers:
Java Classes Job Interview Questions Table of Contents:
1 :: In this example class-var = new classname( );
The classname is the name of the class that is being instantiated.
A) True
B) False
whan we create an object so code are classname obj=new classname();classname is name of the classobj is objectnew is create new instances of class classnameso that ans is true...........what u say
2 :: Tell me Is it possible to declare an anonymous class while implementing an interface?
Interface i = new Interface(){/* Code}The above statement creates an instance of a class which implements the Interface "Interface". As name of class is not specified hence it is anonymous.
3 :: Explain what does enumeration means when talking about the 9th Amendment
Please share your answers.
4 :: How to call two interfaces in one interface?
You can not call 2 interface in interface but you can extend interfaces in your interface.Example :
Interface I1{..}Interface I2 extends I1{..}Interface I3 extends I2{}
Interface I1{..}Interface I2 extends I1{..}Interface I3 extends I2{}
5 :: Explain when we are overloading or overriding the methods how we want to take care about the acess specifiers?
When we override a method in the child class, that method sould not be a private in parent class, but that method should be public or protected or default, those methods should have the same signature.
But we can overload the method within the same class or in the child class but they have some difference in having no of arguments or type of arguments. if we overload the method within the class we can use any access specifier, if we overload in child class dont use private.
But we can overload the method within the same class or in the child class but they have some difference in having no of arguments or type of arguments. if we overload the method within the class we can use any access specifier, if we overload in child class dont use private.
6 :: What is enumeration?
public interface Enumeration . An object that implements the Enumeration interface generates a series of elements, one at a time. Successive calls to the nextElement method return successive elements of the series.
7 :: It is possible to define a class within another class; such classes are known as ____________
A) Nested Classes
this is called as Inner Class also
8 :: The methods and variables defined within a class are called members of the class
A) True
B) False
True
9 :: in Java, all class objects need not be dynamically allocated
A) True
B) False
I think it is true. Because, we use initalize some variables which are not dynamic.
For eg: int i = 10;
For eg: int i = 10;
10 :: Static and Non-Static are the two types of nested classes
A) True
B) False
true.....class declared with static called static inner class....with out static called non static inner class..
11 :: The variable receiving the value returned by a method must also be compatible with the return type specified for the method.
A) True
B) False
it is True the avriable receiving the value must be compatible.
12 :: The new operator dynamically allocates ________ for an object and returns a reference to it.
A) Classes
B) Variables
C) Memory
D) None of the Above
It always allocates memory...
14 :: The Code in java is contained within Methods
A) True
B) False
Source Code is normally an entire file.
In Java the actual execution (or result preparation) would be there in methods only.Method will return exact one return value / 0(void).
Methods will change the behaviour of an object (Operations).
Fields contains value or state of an object.
In Java the actual execution (or result preparation) would be there in methods only.Method will return exact one return value / 0(void).
Methods will change the behaviour of an object (Operations).
Fields contains value or state of an object.
15 :: Explain how to declare and defile a final class without use of final keyword?
By making constructor as 'private', we can make a final class.
16 :: When we create a class, we are creating a new data type
A) True
B) False
well, it isn't /quite/ the same as a struct. A class can contain methods as well as state, remember...
17 :: A class is declared by use of the ________ keyword.
A) Object
B) Class
C) Instance
D) None of the above
D)None of the above.This is because the class is a valid keyword and not Class.This might catch inexperienced programmers who are taught the first letter of the class by convention is capital.
18 :: Java allows objects to initialize themselves when they are created using _________
A) Arguments
B) Classes
C) Constructors
D) Parameters
Ans is constructer.
B'coz When a object is created following things are happen:
1) Memory gets allocated to the object
2) Constructer gets called.
3) In constructer the object gets initialize.
i think this will be sufficient to clear the topic..
B'coz When a object is created following things are happen:
1) Memory gets allocated to the object
2) Constructer gets called.
3) In constructer the object gets initialize.
i think this will be sufficient to clear the topic..
20 :: What is Class Loader?
Class loaders are one of the cornerstones of the Java virtual machine (JVM) architecture. They enable the JVM to load classes without knowing anything about the underlying file system semantics, and they allow applications to dynamically load Java classes as extension modules.A class loader is an object that is responsible for loading classes. The class ClassLoader is an abstract class. Given the name of a class, a class loader should attempt to locate or generate data that constitutes a definition for the class. A typical strategy is to transform the name into a file name and then read a "class file" of that name from a file system.
21 :: In general, there are _________ ways that a computer language can pass an argument to a subroutine
A) One
B) Two
C) Three
D) Four
Explanation: In general, there are two ways that a computer language can pass an argument to a subroutine. The first way is call-by-value. The second way an argument can be passed is call-by-reference.
22 :: Deallocation of memory in Java is called Garbage Collection
A) True
B) False
True, deallocation is called Garbage Collection
23 :: When an overloaded method is invoked, Java uses the type and/or number of arguments as its guide to determine which version of the overloaded method to actually call
A) True
B) False
a) true
the type and number of args is together known as the signature of a method
the type and number of args is together known as the signature of a method
24 :: A variable declared as final prevents its contents from being modified
A) True
B) False
ans is true.
when we a final keyword to a variable the value of the variable can't change.
when we a final keyword to a variable the value of the variable can't change.
25 :: Sometimes a method will need to refer to the object that invoked it. To allow this, Java defines the_____ keyword
A) this
B) that
C) the
D) and
Ans : this.
B'coz 'this' keyword is used to point to the current object.
B'coz 'this' keyword is used to point to the current object.
