¿Puedes tener varios constructores en una clase Java?

Can you have multiple constructors in a class Java?

The technique of having two (or more) constructors in a class is known as constructor overloading. A class can have multiple constructors that differ in the number and/or type of their parameters. It’s not, however, possible to have two constructors with the exact same parameters.

A class can have multiple constructors, as long as their signature (the parameters they take) are not the same. You can define as many constructors as you need. When a Java class contains multiple constructors, we say that the constructor is overloaded (comes in multiple versions).

Yes, an abstract class can have a constructor in Java. You can either explicitly provide a constructor to the abstract class or if you don’t, the compiler will add a default constructor of no argument in the abstract class. This is true for all classes and it also applies to an abstract class.

A subclass needs a constructor if the superclass does not have a default constructor (or has one that is not accessible to the subclass). If the subclass has no constructor at all, the compiler will automatically create a public constructor that simply calls through to the default constructor of the superclass.

There can be multiple constructors in a class. However, the parameter list of the constructors should not be same. This is known as constructor overloading.

To put it simply, you use multiple constructors for convenience (1st example) or to allow completely different initialization methods or different source types (2nd example. For example: Empty constructor (no arguments) for reflection, Constructor has argument(s) for create new instance ( A a = new A(‘foo’, ‘bar’); ).

There can be more than one constructor defined in a class. This is called overloading the constructor.

Yes! 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.

The super keyword in Java is a reference variable which is used to refer immediate parent class object. Whenever you create the instance of subclass, an instance of parent class is created implicitly which is referred by super reference variable. super can be used to invoke immediate parent class method.

The Scala approach to defining multiple class constructors is a little different than Java, but somewhat similar. Rather than try to explain this in words, I just created some example source code to demonstrate how this works. Here’s some source code to demonstrate the Scala “multiple constructors” approach:

With multiple constructors : In a case with the Superclass having multiple constructors, any of those constructors can be called using the primary constructor of the Subclass.

Therefore, you need to use an abstract class whenever a base behavior must have constructor parameters: However, be aware that a class can extend only one abstract class.

For Example, in the following code, the double argument constructor of the Superclass is called by the primary constructor of the Subclass using the extends clause by defining the specific constructor. We can call the single argument constructor here, By default another argument value will be 0.