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How many instances of an abstract class can be created?

How many instances of an abstract class can be created? Correct Answer

0. The answer to the question of how many instances of an abstract class can be created is zero. That is, we cannot create an instance of an abstract class as it does not have any complete implementation.

Related Questions

Which of the following is/are true for an abstract class?
1. A class is declared abstract by prefacing the definition with the word abstract.
2. A class is declare abstract by using the keyword implements.
3. It is a class that really isn’t supposed to ever be instantiated but instead serves as a base class.
4. Attempting to instantiate an abstract class results in an error.
Which of the following is/are true for an abstract class? i) Abstract classes in PHP are declared with the help of abstract keyword. ii) A class is declare abstract by using the keyword implements. iii) It is a class that really isn’t supposed to ever be instantiated but instead serves as a base class. iv) Attempting to instantiate an abstract class results in an error. 
interface Base{ boolean m1 (); byte m2(short s);}

which two code fragments will compile?
1. interface Base2 implements Base {}2. abstract class Class2 extends Base { public boolean m1(){ return true; }}3. abstract class Class2 implements Base {}4. abstract class Class2 implements Base { public boolean m1(){ return (7 > 4); }}5. abstract class Class2 implements Base { protected boolean m1(){ return (5 > 7) }}
Which two classes use the Shape class correctly?
A. public class Circle implements Shape { private int radius; }B. public abstract class Circle extends Shape { private int radius; }C. public class Circle extends Shape { private int radius; public void draw(); }D. public abstract class Circle implements Shape { private int radius; public void draw(); }E. public class Circle extends Shape { private int radius; public void draw() { /* code here */ } }F. public abstract class Circle implements Shape { private int radius; public void draw() { /* code here */ } }
Which two of the following are legal declarations for abstract classes and interfaces?
1. final abstract class Test {}
2. public static interface Test {}
3. final public class Test {}
4. protected abstract class Test {}
5. protected interface Test {}
6. abstract public class Test {}
Consider the following snapshot of a system running n concurrent processes. Process i is holding Xi instances of a resource R, 1 ≤ i ≤ n. Assume that all instances of R are currently in use. Further, for all i, process i can place a request for at most Yi additional instances of R while holding the Xi instances it already has. Of the n processes, there are exactly two processes p and q such that Yp = Yq = 0. Which one of the following conditions guarantees that no other process apart from p and q can complete execution?
In a system, there are three types of resources and four processes that execute concurrently. At the outset, the processes have declared their maximum resource requirements using a matrix named Max as given below. For example, Max[ ] is the maximum number of instances of that would require. The number of instances of the resources allocated to the various processes at any given state is given by a matrix named Allocation. Consider a state of the system with the Allocation matrix as shown below, and in which 3 instances of E and 3 instances of F are the only resources available. Allocation   E F G P0 1 0 1 P1 1 1 2 P2 1 0 3 P3 2 0 0   Max   E F G P0 4 3 1 P1 2 1 4 P2 1 3 3 P3 5 4 1   From the perspective of deadlock avoidance, which one of the following is true?
In a logistic regression problem an instance is similar to 60 positive instances, 20 negative instances, dissimilar to 30 positive instances, 90 negative instances. What kind of an instance is this?
There are five classes class 1, class 2, class 3, class 4 and class 5 in a school. They are one above the other. Class 1 is at the bottom, then class 2 above it and so on. Five videos M1, M2, M3, M4 and M5 are displayed in these given classes. Only one video is displayed in a particular class. Each video is displayed only one time. Video M5 is displayed at an even numbered class. Video M2 is displayed at class 1. Video M1 is displayed at the class just below M5. Video M4 is not displayed at even numbered class. Which of the following statement is not correct?
Abstract class A has 4 virtual functions. Abstract class B defines only 2 of those member functions as it extends class A. Class C extends class B and implements the other two member functions of class A. Choose the correct option below.