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
Boolean is a class and is not a keyword.
Answer : D
Explaination
The double data type is represented by double-precision 64-bit IEEE 754 floating point.
Answer : A
Explianation
Byte variable has default value of 0 if defined as an instance/static variable.
Q 4 - What is polymorphism?
A - Polymorphism is a technique to define different objects of same type.
B - Polymorphism is the ability of an object to take on many forms.
C - Polymorphism is a technique to define different methods of same type.
Answer : B
Explaination
Polymorphism is the ability of an object to take on many forms. The most common use of polymorphism in OOP occurs when a parent class reference is used to refer to a child class object.
Q 5 - What is local variable?
A - Variables defined inside methods, constructors or blocks are called local variables.
B - Variables defined outside methods, constructors or blocks are called local variables.
C - Static variables defined outside methods, constructors or blocks are called local variables.
Answer : A
Explaination
Variables defined inside methods, constructors or blocks are called local variables. The variable will be declared and initialized within the method and it will be destroyed when the method has completed.
Answer : A
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 7 - Dynamic binding uses which information for binding?
Answer : B
Explaination
Dynamic binding uses object information for binding.
Q 8 - What happens when thread's sleep() method is called?
A - Thread returns to the ready state.
Answer : B
Explaination
When a task invokes its sleep() method, it returns to the waiting state.
Answer : B
Explaination
No, constructor cannot be inherited.
Q 10 - This is the parent of Error and Exception classes.
Answer : A
Explaination
Throwable is the parent of both Error and Exception class.
