An instance of a class is also known as an object. In the Java language, you use the new operator. Here is an example:
Integer x; // Using the wrapper class, Integer. This doesn't create the object yet.
x = new Integer(5); // This will create the instance.
These commands can be combined into one:
Integer x = new Integer(5);
class MyClass extends AnotherClass {}
They are inversely related. That is: If you declare a method as final you cannot overridden in the child class If you declare a class as final you cannot inherit it in any other class.
when overriding of a class or a method is necessary, they can be declared as abstract
To scope class members to the class (rather than to instances of the class), declare them as static members of the class. Static members are accessible even when no instances of the class exist. As such, static member functions do not have access to a 'this' pointer, unlike ordinary (nonstatic) member functions.
Yes, you can declare and define the constructor within a class. A constructor is a special member function of a class that is automatically called when an object of the class is created. It is used to initialize the object's data members. The constructor can be declared and defined within the class definition or can be defined outside the class definition using the scope resolution operator (::).
Declare it final.
if we declare a method as final then it can be changed.
You can declare a class as "final".
Declare the class as final. final class A{ ... }
no one is sure about it thwt when it is going to declare
class MyClass extends AnotherClass {}
They are inversely related. That is: If you declare a method as final you cannot overridden in the child class If you declare a class as final you cannot inherit it in any other class.
when overriding of a class or a method is necessary, they can be declared as abstract
It is dependent on the requirement of your usage of the Object of that class
By using the final keyword in the class declaration statement. Ex: public final class Test {...}
It will get a compiler error in Java.
To scope class members to the class (rather than to instances of the class), declare them as static members of the class. Static members are accessible even when no instances of the class exist. As such, static member functions do not have access to a 'this' pointer, unlike ordinary (nonstatic) member functions.