An abstract class is declared using the keyword abstract.
It may or may not contain abstract methods.
An abstract class must be inherited by some other class.
If the derived class does not provide the implementation of any abstract method present in an abstract class, the derived class must be declared as abstract.
Objects of an abstract class cannot be created, but reference can be created.
Through the reference of an abstract class, only methods of the abstract class implemented in the derived class can be called.
The abstract keyword cannot be applied to static methods or constructors.
abstract class Base
{
abstract void show();
}
class first extends Base
{
void show()
{
System.out.println("show of first");
}
}
class second extends Base
{
void show()
{
System.out.println("show of second");
}
}
abstract class third extends Base
{
}
public class Abstract_method {
public static void main(String[] args) {
// TODO Auto-generated method stub
Base b = new first();
b.show();
b = new second();
b.show();
}
}
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