·
Encapsulation
Linking of data and methods
within an object is called
encapsulation. By linking data and
methods together the data can be changed
only via the methods. Encapsulation allows us to implement information hiding
Information
hiding has two aspects
Hiding
data
An object data con not be changed
except by using its own fixed methods. This is important because it protects
the data inside and object from external influences.
Hiding of Implementation Details
How the methods perform. Their jobs
are hidden from the user.
·
Inheritance
Classes can be organized hierarchy.
Concept of one class of objects inheriting the data and behavior from another
class of objects. This will allow new classes
to be derived from existing
classes.
·
Polymorphism
Polymorphism means that
objects belonged to different classes
can respond to the same message in different
ways.
This can be done in 2 ways
Overriding
Overloading
Overriding - A sub class inherits the methods from the super class and
redefines it by filling it with its own instructions. This is done by
defining a methods in the sub class that has the same name same arguments and
same return type as the super class’s
methods.
Overloading - Single class can have
two or more methods with the same name
but with different parameters. The
difference may be in the no of
parameters, the data types or both.
·
Multithreading
Java allows the programmer to run
several independent parts of the same program concurrently. (They appear to be
running at the same time)
Ex: Scrolling while on animation
is happening
More useful in graphical user
interface
Java Development Kit – JDK
JDK is a set of command line tools
that can be use to create java programs
Note: Java is
Case-Sensitive language
Java is a small software. It will
not provide a particular IDE like in VB,
Pascal, C
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