Defining an abstract class without any abstract methods

Question

Of course.

Declaring a class abstract only means that you don't allow it to be instantiated on its own.

Declaring a method abstract means that subclasses have to provide an implementation for that method.

The two are separate concepts, though obviously you can't have an abstract method in a non-abstract class. You can even have abstract classes with final methods but never the other way around.

Yes you can do it. Why don't you just try doing that?

Yes you can. The abstract class used in java signifies that you can't create an object of the class. And an abstract method the subclasses have to provide an implementation for that method.

So you can easily define an abstract class without any abstract method.

As for Example :

public abstract class AbstractClass{

    public String nonAbstractMethodOne(String param1,String param2){
        String param = param1 + param2;
        return param;
    }

    public static void nonAbstractMethodTwo(String param){
        System.out.println("Value of param is "+param);
    }
}

This is fine.

YES You can create abstract class with out any abstract method the best example of abstract class without abstract method is HttpServlet
Abstract Method is a method which have no body, If you declared at least one method into the class, the class must be declared as an abstract its mandatory BUT if you declared the abstract class its not mandatory to declared the abstract method inside the class.

You cannot create objects of abstract class, which means that it cannot be instantiated.

Yes we can have an abstract class without Abstract Methods as both are independent concepts. Declaring a class abstract means that it can not be instantiated on its own and can only be sub classed. Declaring a method abstract means that Method will be defined in the subclass.

Yes, you can declare a class you cannot instantiate by itself with only methods that already have implementations. This would be useful if you wanted to add abstract methods in the future, or if you did not want the class to be directly instantiated even though it has no abstract properties.

yes, we can declare an abstract class without any abstract method. the purpose of declaring a class as abstract is not to instantiate the class.

so two cases

1) abstract class with abstract methods.

these type of classes, we must inherit a class from this abstract class and must override the abstract methods in our class, ex: GenricServlet class

2) abstract class without abstract methods.

these type of classes, we must inherit a class from this abstract class, ex: HttpServlet class purpose of doing is although you if you don't implement your logic in child class you can get the parent logic

please check the HttpServlet source code