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We can also define more than one constructor with different arguments. We can use the abstract class to get the values from concrete classes. When we have defined final fields in the abstract class, but they are not initialized in the declaration, the constructor can be used to initialize these fields.

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tutorials that's easy to understand for both beginner and advanced Consider the Terrier class below. If we dont define a constructor, the JVM will define a default one for us.

constructor

A constructor is used to initialize an object called by its name, and the constructors name is the same as the classs name.

Learn if you can create an abstract class constructor in Java and when you should create one.

The subclass constructors can call one constructor from the abstract class, and they will have to call it if there is no argument constructor in the abstract class.

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. The variable is initialized when an instance of the subclass is created and then cant be changed. So yes, you can create an abstract class constructor in Java when you need to. The variables dont have to be final variables, but if your abstract class has one or more variables, and you want them to be initialized on instantiation, then you need to create the constructor.

The main method also demonstrates that we can not instantiate the Abstract class not. This tutorial demonstrates how to create a constructor in an abstract class in Java. Before defining a constructor, we must consider the following points.

This means that by default, even an abstract class in Java has a default constructor that does nothing. if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[728,90],'delftstack_com-medrectangle-4','ezslot_3',125,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-delftstack_com-medrectangle-4-0')};Output: DelftStack articles are written by software geeks like you. For example, suppose you have an abstract class named Dog as shown below: In the above Dog abstract class, a constructor is defined to initialize the final variable breed.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'metapx_org-box-4','ezslot_2',105,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-metapx_org-box-4-0')}; This constructor can be called from any class that extends the Dog class.

When we want to perform initialization to the fields of an abstract class before the instantiation of a subclass is done.

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When you define a Java class construct, the Java compiler automatically creates a constructor with no argument during the execution of the program. The only difference is that you cant instantiate an abstract class, so you need to extend it and call the constructor using super().

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Finally, an abstract class constructor behaves just like any other class type. The two concrete classes, Salary and Tax, calculate the gross salary and tax.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[336,280],'delftstack_com-medrectangle-3','ezslot_2',113,'0','0'])};if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-delftstack_com-medrectangle-3-0')}; Abstract constructors are frequently used for salary calculation. When we indicate that a class is abstract, it can not be instantiated, but that doesnt mean it cannot have the constructor. The abstract class can have a constructor in two conditions.

All the constructors should be defined as protected in the abstract class because defining them as the public has no benefit.

There is one condition when you might want to define a constructor in an abstract class, and that is when you want to enforce that all subclasses of the superclass have specific member variables initialized.

It calls the Dog constructor by calling the super() method in its constructor: By creating an abstract class that has a constructor, you ensure that its subclasses will have the final variable initialized.

The abstract class is declared with an abstract keyword, abstract classes also have a constructor, and if we dont define any constructor in the abstract class, then JVM will give us a default one.

Lets have an example for the abstract class constructor that will calculate the gross salary, tax, and net salary by extending the abstract class with the constructor.

An abstract class cant be instantiated directly, so you need to call super() from the subclass constructor to execute the abstract constructor.

The superclass SalaryCal is declared abstract and has two constructors, one without arguments which is the default, and the other with arguments.