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A constructor should be overloaded when there is a parameter with default value that is commonly used, or if it is possible that not all the information for creating the instance will be gathered all at once. As an example, say there is a class that describes bank accounts. Assuming I can choose to deposit or not deposit money under my name upon creating an account, there is a chance for a meaningful overload. One constructor could take in the name of the account owner and the initial balance as parameters; the overloaded constructor could just take the name as a parameter while setting the initial balance to zero.
Wiki User
∙ 15y ago
Wiki User
∙ 14y agoIn Java constructors cannot be overridden because they are not inherited. You can have a constructor of the same name and signature in your subclass, but it will simply hide the one in the superclass.
Wiki User
∙ 12y agoOverloading a constructor means typing in multiple versions of the constructor, each having a different argument list, like the following examples:
class Car {
Car() { }
Car(String s) { }
}
The preceding Car class has two overloaded constructors, one that takes a string, and one with no arguments.
Wiki User
∙ 12y agoNo. You cannot override the constructor. You can only overload them.
You can argue that, during inheritance if you provide a child class constructor it should override the parent class constructor. Unfortunately, that doesnt happen. The parent class constructor will get called eventually and you cant block it.
Such a situation is called Constructor Chaining
Constructor Chaining
We know that constructors are invoked at runtime when you say new on some class type as follows:
Lamborghini h = new Lamborghini();
But what really happens when you say new Lamborghini() ? (Assume Lamborghini extends Car and Car extends Object.)
1. Lamborghini constructor is invoked. Every constructor invokes the constructor of its superclass with an (implicit) call to super(),
2. Car constructor is invoked (Car is the superclass of Lamborghini).
3. Object constructor is invoked (Object is the ultimate superclass of all classes, so class Car extends Object even though you don't actually type "extends Object" into the Car class declaration. It's implicit.) At this point we're on the top of the hierarchy.
4. Object instance variables are given their explicit values. By explicit values, we mean values that are assigned at the time the variables are declared, like "int x = 27", where "27" is the explicit value (as opposed to the default value) of the instance variable.
5. Object constructor completes.
6. Car instance variables are given their explicit values (if any).
7. Car constructor completes.
8. Lamborghini instance variables are given their explicit values (if any).
9. Lamborghini constructor completes.
Wiki User
∙ 13y agoNo. A constructor cannot be overridden. It can only be overloaded
Wiki User
∙ 14y agoMake multiple constructors, each with a different set of parameters.
Wiki User
∙ 12y agoYes. You can have multiple constructors with the same name and with different arguments
Wiki User
∙ 13y agoyes, you can overload constructors in Java. You can have more than one constructor for a single class and each should have a different set of parameters.
Wiki User
∙ 11y agono
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How do you get a default constructor?
The default constructor is an empty (only call the super constructor) with no parameters constructor inserted by the java compiler when you don't define a constructor in your class. If you write something like this: public class NoConstructorClass{ //no constructor goes here } Then you get something like this: public class NoConstructorClass{ public NoConstructorClass(){ // Default constructor that you didn't write super(); } }
Can a constructor be declared as virtual?
A constructor cannot be virtual because at the time when the constructor is invoked the virtual table would not be available in the memory. Hence we cannot have a virtual constructor. ## Constructor called implicitly not explicitly so constructor is not virtual.
Default constructor in java?
If you don't type a constructor into your class code, a default constructor will be automatically generated by the compiler. The default constructor is ALWAYS a no-arg constructor. (Obviously the compiler has no clue what all arguments you might want for your class. So it takes the safe way out with a no argument constructor) A no-arg constructor is not necessarily the default (i.e., compiler-supplied) constructor, although the default constructor is always a no-arg constructor. The default constructor is the one the compiler provides! While the default constructor is always a no-arg constructor, you're free to put in your own no-arg constructor.
What is an empty constructor?
An empty constructor takes no arguments and calls the default constructor
What is the difference between implicit and explicit call of constructor in c plus plus?
An implicit constructor call will always call the default constructor, whereas explicit constructor calls allow to chose the best constructor and passing of arguments into the constructor.
What is first call in struts2 default constructor or validate method?
Default Constructor will be called first . If you override Validate method , then validate method will be called .
Why you require constructor in cpp?
Constructors are not a requirement of CPP. A default constructor and copy constructor are automatically generated by the compiler for every class you create when no constructors are declared. The only time you need to declare a constructor is when you wish to override the default behaviour of the generated constructors, to ensure the class is correctly initialised. When any constructor is declared, the default constructor is no longer generated by the compiler -- you must define your own default constructor (one that has no parameters, or where all the parameters have default values). The copy constructor is always generated for you regardless of how many other constructors you declare. But if the class contains pointers to allocated memory that is "owned" by the class then you must override the generated copy constructor with your own copy constructor. This is to ensure the memory is deep copied (the generated copy constructor only performs a shallow, member-wise copy of the members). Otherwise two objects of the same class will end up pointing at the same memory, which would be disastrous if either one were to be deleted. The other instance would be automatically invalidated because it would point to memory that was released by the other instance's destructor.
What is the method of constructor overloading?
The first thing to note about constructor overloading is that Java creates a no argument constructor for you if and only if you have not typed a constructor yourself. Every class has a constructor even abstract ones (default no argument constructor). Abstract constructors are always executed. To overload a constructor you can do the following: class Test { String name; Test(String n) { name = n; System.out.println("Constructing Test Object named: " + name); } } In the case above we are overloading the default no argument constructor with a constructor that takes a String parameter. You can write you own no argument constructor as follows: class Test { Test() { System.out.println("Constructing Test Object"); } } To override our own no argument constructor we do this: class Test { Test() { // our no argument constructor System.out.println("Constructing Test Object"); } String name; Test(String n) { // overloading our no argument constructor with this // constructor that take a String parameter name = n; System.out.println("Constructing Test Object named: " + name); } }
How do you get a default constructor?
The default constructor is an empty (only call the super constructor) with no parameters constructor inserted by the java compiler when you don't define a constructor in your class. If you write something like this: public class NoConstructorClass{ //no constructor goes here } Then you get something like this: public class NoConstructorClass{ public NoConstructorClass(){ // Default constructor that you didn't write super(); } }
Can a constructor be declared as virtual?
A constructor cannot be virtual because at the time when the constructor is invoked the virtual table would not be available in the memory. Hence we cannot have a virtual constructor. ## Constructor called implicitly not explicitly so constructor is not virtual.
Default constructor in java?
If you don't type a constructor into your class code, a default constructor will be automatically generated by the compiler. The default constructor is ALWAYS a no-arg constructor. (Obviously the compiler has no clue what all arguments you might want for your class. So it takes the safe way out with a no argument constructor) A no-arg constructor is not necessarily the default (i.e., compiler-supplied) constructor, although the default constructor is always a no-arg constructor. The default constructor is the one the compiler provides! While the default constructor is always a no-arg constructor, you're free to put in your own no-arg constructor.
What is an empty constructor?
An empty constructor takes no arguments and calls the default constructor
What is the difference between implicit and explicit call of constructor in c plus plus?
An implicit constructor call will always call the default constructor, whereas explicit constructor calls allow to chose the best constructor and passing of arguments into the constructor.
When a object is passed to a function as argument why it is not generating an error if the parameterized constructor is defined and not the default constructor?
default constructor is used only when the programmer does not use a constructor to initialize objects. Once the programmer defines a constructor then the default constructor is no longer used
Can you call constructor?
yes we can call constructor
What is use of constructor in java?
Constructor is used to do something (written in constructor) immediately after object creation.
What is a default parameterized constructor?
There is no such thing as a default parameterized constructor. The default constructor is always the 'no-arg' constructor and does not take any parameters or arguments as input
