Java Online Quiz
Following quiz provides Multiple Choice Questions (MCQs) related to Core Java. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.
Answer : B
Explaination
Objects are allocated memory in heap memory space.
Answer : B
Explaination
No, a java file can contain only one public class.
Answer : B
Explaination
float variable has default value of 0.0f if defined as an instance/static variable.
Q 4 - Which of the following is true about super class?
Answer : D
Explaination
All of the above are correct.
Q 5 - What is an immutable object?
A - An immutable object can be changed once it is created.
B - An immutable object can't be changed once it is created.
C - An immutable object is an instance of an abstract class.
Answer : B
Explaination
An immutable object can't be changed once it is created. String objects are immutable.
Q 6 - What kind of variables a class can consist of?
A - class variables, instance variables
Answer : B
Explaination
A class consist of Local variable, instance variables and class variables.
Q 7 - What is composition?
A - Composition is a data structure.
B - Composition is a way to create an object.
C - Holding the reference of the other class within some other class is known as composition.
Answer : C
Explaination
Holding the reference of the other class within some other class is known as composition. It represents a HAS-A relationship. For example, a Student has a Pen. Here Student class has Pen as its instance variable.
Q 8 - What is Deserialization?
A - Deserialization is the process of restoring state of an object from a byte stream.
B - Serialization is the process of restoring state of an object from an object.
Answer : A
Explaination
Deserialization is the process of restoring state of an object from a byte stream.
Q 9 - Which arithmetic operations can result in the throwing of an ArithmeticException?
Answer : A
Explaination
Integer / and % can result in the throwing of an ArithmeticException.
Q 10 - What is currentThread()?
A - It is a Thread public static method used to obtain a reference to the current thread.
B - It is a thread's instance method used to get thread count.
C - It is a object's public static method used obtain a reference to the current thread.
D - It is a object's instance method used to get thread count.
Answer : A
Explaination
currentThread() is a public static method of Thread class used to obtain a reference to the current thread.
