What are the OOPS concepts?

1) Encapsulation: It is the mechanism that binds together
code and data in manipulates, and keeps both safe from
outside interference and misuse. In short it isolates a
particular code and data from all other codes and data. A
well-defined interface controls the access to that
particular code and data.
2) Inheritance: It is the process by which one object
acquires the properties of another object. This supports
the hierarchical classification. Without the use of
hierarchies, each object would need to define all its
characteristics explicitly. However, by use of inheritance,
an object need only define those qualities that make it
unique within its class. It can inherit its general
attributes from its parent. A new sub-class inherits all of
the attributes of all of its ancestors.
3) Polymorphism: It is a feature that allows one interface
to be used for general class of actions. The specific
action is determined by the exact nature of the situation.
In general polymorphism means "one interface, multiple
methods", This means that it is possible to design a
generic interface to a group of related activities. This
helps reduce complexity by allowing the same interface to
be used to specify a general class of action. It is the
compiler's job to select the specific action (that is,
method) as it applies to each situation

Object oriented programming organizes a program around it's
data i.e objects and a set of well defined interface to
that data. An Object-oriented program can be characterized
as data controlling access to code.