Abstract Class Are Protected

Java abstract classes and methods data abstraction is the process of hiding certain details and showing only essential information to the user. An abstract class can be subclassed but it cant be instantiated if a class defines one or more abstract methods then the class itself must be declared abstract an abstract class can declare both abstract and concrete methods. Example of abstract class.

That is an abstract method cannot add static or final modifier to the declaration.

Abstract class are protected. You cannot instantiate them and they may contain a mix of methods declared with or without an implementation. The abstract keyword is a non access modifier used for classes and methods. Following is an example for java abstract method. It is not possible to modify an abstract class with the sealed modifier because the two modifiers have opposite meanings.

It can have abstract and non abstract methods. The sealed keyword enables you to prevent the inheritance of a class or certain class members that were previously marked virtual. It cannot be instantiated. An abstract class cannot be instantiated.

Abstract classes and class members. Lsp is about writing derived classes which are inter changable as per the base class interface but the question is about base classes with all protected members so theres no common public interface to speak of and the lsp doesnt really bring any useful insight. An abstract class must be declared with an abstract keyword. However with abstract classes you can declare fields that are not static and final and define public protected and private concrete methods.

Abstract classes are similar to interfaces. Abstraction can be achieved with either abstract classes or interfaces which you will learn more about in the next chapter. An abstract class may contain abstract methods and accessors. It can have final methods which will force the subclass not to change the body of the method.

The sealed modifier prevents a class from being inherited and the abstract modifier requires a class to be inherited. A java class containing an abstract class must be declared as abstract class. It can have constructors and static methods also. The abstract keyword enables you to create classes and class members that are incomplete and must be implemented in a derived class.

An abstract method can only set a visibility modifier one of public or protected.