Question { 10092 }

Describe inheritance as applied to java?

Answer

Inheritance is one of the OOPS concepts(the OOPS concepts
are Abstraction,Encapsulation,Polymorphism and Inheritance).
Java is purely a OOP language.

Inheritance is the ability of a class to use member data
and methods of another class.This is done by deriving a
class from a diff class.The class from which it derives is
called the base or the parent or super class and the class
which derives is called the derived or the child or sub
class.

Java supports two types of inheritance SINGLE inheritance
and MULTILEVEL inheritance."extends" is the keyword to
inherit properties of the base class.All the derived
classes having a single base class is termed as the single
inheritance.for example
class A
{
...
}
class B extends A
{
...
}
public class C extends A
{
...
}
this is single inheritance

whereas, a class inherits the properties of another class,
for example
class A
{
...
}
class B extends A
{
...
}
public class C extends B
{
...
}

java doesnot support multiple inheritance.However, a class
can implement any number of interfaces(interface is a
collections of methods with no definition(abstract methods))

Question { 12144 }

what is a package?

Answer

Package in java is a collection of classes and interfaces
that can be reused in any application or applet.