Yes, abstract class can declare and define constructor in Java. Since you can not create instance of abstract class,  constructor can only be called during constructor chaining, i.e. when you create instance of concrete implementation class. Now the question is, What is the purpose of constructor, if you can not instantiate abstract class? Well, it...

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Yes, abstract class can implement interface by using implements keyword. Since they are abstract, they don’t need to implement all methods. It’s good practice to provide an abstract base class, along with an interface to declare Type. One example of this is java.util.List interface and corresponding java.util.AbstractList abstract class. Since Abst...

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A class is called abstract when it is declared with keyword abstract. Abstract class may contain abstract method. It can also contain n numbers of concrete method. Interface can only contain abstract methods. Abstract Class Interface Abstract class can have concrete and abstract methods. Interface can have only abstract methods. The abstract class ...

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No, abstract class can not be final in Java. Making them final will stop abstract class from being extended, which is the only way to use abstract class. They are also opposite of each other, abstract keyword enforces to extend a class, for using it, on the other hand, final keyword prevents a class from being extended. We can not make a class as a...

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Yes, abstract class can declare and define static methods, nothing prevents from doing that. But, we must follow guidelines for making a method static in Java, as it’s not welcomed in a object oriented design, because static methods can not be overridden in Java. abstract class Car {     private static final String tagLine = "Dont drink and Driv...

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No, we can not create instance of abstract class in Java, they are incomplete. Even though, if your abstract class don’t contain any abstract method, we can not create instance of it. By making a class abstract,  we told compiler that, it’s incomplete and should not be instantiated. If a code tries to instantiate an abstract class Compiler will thr...

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No, It’s not mandatory for an abstract class to have any abstract method. You can make a class abstract in Java, by just using abstract keyword in class declaration. And inside the abstract class you can define body for all the available methods (concentrate methods). But abstract class should have abstract methods, because that’s the first thing y...

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An abstract method is a method without body. We just declare method, without defining it and use abstract keyword in method declaration. All method declared inside Java Interface are by default abstract. Remember we need to declare the class also as an abstract class which has any abstract method. Following is an example of a class with abstract me...

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Consider using abstract classes if any of these statements apply to your situation: You want to share code among several closely related classes. You expect that classes that extend your abstract class have many common methods or fields, or require access modifiers other than public (such as protected and private). You want to declare non-static or...

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No, The same logic goes with a class also. We can not declare both abstract and final at a time. Abstract means incomplete and its leaves the responsibility of implementation to child classes. Where final means complete and its restrict the child to implement. To check this for a Class click here.

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