Question: What Happens When A Class With Parameterized Constructor And Having No Default Constructor Is Used?

Can a constructor be private?

Yes, we can declare a constructor as private.

If we declare a constructor as private we are not able to create an object of a class.

We can use this private constructor in the Singleton Design Pattern..

Can you have a constructor with all default arguments?

Like all functions, a constructor can have default arguments. They are used to initialize member objects. … Note that if a constructor has any arguments that do not have default values, it is not a default constructor. The following example defines a class with one constructor and two default constructors.

Can a constructor call another constructor?

Yes, any number of constructors can be present in a class and they can be called by another constructor using this() [Please do not confuse this() constructor call with this keyword]. this() or this(args) should be the first line in the constructor. This is known as constructor overloading.

What happens if there is no constructor defined in a class?

If we don’t define a constructor in a class, then compiler creates default constructor(with no arguments) for the class. And if we write a constructor with arguments or no-arguments then the compiler does not create a default constructor. Default constructor provides the default values to the object like 0, null, etc.

Why do we need parameterized constructor?

The parameterized constructors are the constructors having a specific number of arguments to be passed. The purpose of a parameterized constructor is to assign user-wanted specific values to the instance variables of different objects.

What will happen if only one parameterized constructor is explicitly defined?

What would be the behaviour if one parameterized constructor is explicitly defined? Explanation: The class compiles successfully. But the object creation of that class gives a compilation error.

Can a class have no constructor?

It is possible for a class to have no constructor. (An important distinction to draw here is that the JVM does not require all class files to have a constructor; however, any class defined in Java does have a default constructor if a constructor is not explicitly declared.

How many default constructors can a class have?

one default constructorA class can only have one default constructor.

What are the rules of constructor?

Rules for ConstructorA 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.Dec 2, 2020

What is the purpose of a destructor?

Destructors are usually used to deallocate memory and do other cleanup for a class object and its class members when the object is destroyed. A destructor is called for a class object when that object passes out of scope or is explicitly deleted. A destructor takes no arguments and has no return type.

Can we have parameterized constructor without default constructor?

If there is any one parametrized Constructor present in a class, Default Constructor will not be added at Compile time. So if your program has any constructor containing parameters and no default constructor is specified then you will not be able to create object of that class using Default constructor.

What happens if you don’t declare a default constructor?

When you do not explicitly write a no-argument constructor for a class, the compiler won’t complain as long as objects are built without parameter constructors. (since compiler allows default constructor to create objects, which itself gives call to no-argument constructor).