Can an abstract class have a constructor?
A constructor is used to initialize an object not to build the object. As we all know abstract classes also do have a constructor. It must be declared with an abstract keyword. It can have a constructor, static method.
Does a constructor have to have the same name as its class?
The name of the constructor must be the same as the name of the class and, if you provide more than one constructor, the arguments to each constructor must differ in number or in type from the others. You do not specify a return value for a constructor.
Why does abstract class have constructor?
In abstract class, we have an instance variable, abstract methods, and non-abstract methods. We need to initialize the non-abstract methods and instance variables, therefore abstract classes have a constructor.
Can we have constructor in abstract class Mcq?
Abstract class cannot have a constructor. Explanation: No instance can be created of abstract class.
Can constructor have any name?
Yes, the constructor should always have the same name as the class. It does not have a return type and its name is same as the class name.
Can constructors have parameters?
Typically, the constructor initializes the fields of the object that need initialization. Java constructors can also take parameters, so fields can be initialized in the object at creation time.
Can abstract class inherit another abstract class?
Yes you can inherit abstract class from another abstract class.
Can abstract keyword be used with constructor?
Since you cannot override a constructor you cannot provide body to it if it is made abstract. Therefore, you cannot use abstract keyword with the constructor.
What are the rules of constructor?
Rules for Constructor
- A constructor cannot have a return type.
- A constructor must have the same name as that of the Class.
- Constructors cannot be marked static.
- A constructor cannot be marked abstract.
- A Constructor cannot be overridden.
- A Constructor cannot be final.
Can abstract class have only abstract methods?
An abstract class is a class that is declared abstract —it may or may not include abstract methods. Abstract classes cannot be instantiated, but they can be subclassed. When an abstract class is subclassed, the subclass usually provides implementations for all of the abstract methods in its parent class.
Can multiple constructors have the same name?
A user can implement constructor overloading by defining two or more constructors in a class sharing the same name. C# can distinguish the constructors with different signatures. i.e. the constructor must have the same name but with different parameters list.
Can method and constructor have same name?
Yes, It is allowed to define a method with the same name as that of a class. Normally the constructor name and class name always the same in Java.
Can abstract classes have constructors?
Abstract classes can have constructors! Yes, when we define a class to be an Abstract Class it cannot be instantiated but that does not mean an Abstract class cannot have a constructor. Each abstract class must have a concrete subclass which will implement the abstract methods of that abstract class.
Should the constructor have the same name as the class?
Yes, the constructor should always have the same name as the class. Constructor looks like method but it is not. It does not have a return type and its name is same as the class name. Mostly it is used to instantiate the instance variables of a class. If the programmer doesn’t write a constructor the compiler writes a constructors on his behalf.
Can an abstract class have a member variable?
an abstract class can have member variables that needs to be initialized,so they can be initialized in the abstract class constructor and this constructor is called when derived class object is initialized. Constructors on abstract types can be called only by derived types.
What is constructor in Java?
Constructor: Constructor is always called by its class name in a class itself. A constructor is used to initialize an object not to build the object. An abstract class also has a constructor. if we don’t define any constructor inside the abstract class then JVM (Java Virtual Machine) will give a default constructor to the abstract class.