1.LANGUAGE
2.JAVA BUZZWORDS
3.CLASS
4.OBJECTS
5.JAVA PROGRAMING STRUCTURE
6.CONTROL STRUCTURES
7.METHODS & FUNCTIONS
8.POLYMORPHISM
9.CONSTRUCTORS
1.LANGUAGE:
************
Language is nothing but which communicates two objects
in real world. Language establishes communication between hardware and software components.
2.JAVA BUZZWORDS:
****************
SIMPLE:
java is simple to develop for large scale application
like windows/web based applications.
ARCHITECTURAL NEUTRAL:
it can run in any type of h/w architecture.
PORTABLE:
it can run on any type of Operating System.
ROBUST:
In some cases,there is a change of some run time errors
to occur in the case of program execution then abnormal
program termination is occur,so that the data and
application may be lost.such type of errors is called
Exception.
if any language is handled these exceptions then that \
language is called strictly written language.these languages
are provide safety and security.
DYNAMIC:
Every object will be allocated dynamic to reduce the
memory wastage.
INTERPRETOR:
In any languages translation is handled by compilers
,but in the java,program is first compiled by the javac
then it will generate code called bytecode.
DISTRIBUTED:
Java is net based application so that we have to share
the data and application among different users.
HIGH PERFORMANCE:
Even though more than 1 user is passing thier requests
at a time.
MULTITHREADED:
More than one program run simultaneously.
SECURE:
Java provides xlent security from unauthorized actions
and provides firewall actions also.
OBJECT-ORIENTED:
Java is object oriented approach.it suports all
the concepts oops such as data abstraction,encapsulation
,polymarphism and inheritance.
CLASS:
******
class is a collection of properties and behaviour.
behavior is nothing but a functions, properties are nothing
but a variables.
<access-specifiers> <modifiers> class class-name
{
// propeties
//behaviours
}
program:
OBJECT:
********
Object is nothing but a entity in a real world.chair,chalkpiece
all r objects.
in language view object is nothing but a reference of a class
when ever create an object it occupies some memory with the class
content.So with this is reference we are utilizing the class.
object creation:
class-name obj=new class-name(<parametes-list>);
new is same as 'malloc' in c is used to create memory location for
object in memory.
**objects store the addresses just like pointers in c.**
---------------------------------------------------------
program:
JAVA PROGRAMING STRUCTURE:
****************************
Components:
1.package declaration part
2.package import statement part
3.class definations.
CONTROL STRUCTURES:
********************
Three types
1.selection(if,switch)
2.iteration(for,while,do-while)
3.jump(return,break)
program:
METHODS/FUNCTIONS:
******************
******************
These are reusable components.Every function should have the
return type.If any function does not return any value then return
type should be declared as void.
<access-specifiers> <modifiers> return-type methodname(parameters-list)
{
//body
//return statement if return type is other than void.
}
program:
POLYMORPHISM
*******************
POLYMORPHISM has two types method overloading and operator
overloading but in java operator oveloading is not supported.
Method overloading is nothing but we can use single names for
multiple purposes.it has same name but its parameters should
be different.
program:
CONSTRUCTORS:
*************
Constructor is a special type of member function.it is
used to initilize the member variable at the time creating object
Rules:
1.Constructor name should be equal with class name.
2.it does not return any value so it shouldnt have the
return type even void also.
3.we can define more than one constructors in a class.
*4.these are not inheritable.
5.it has a implicit call.these are invoked at the time
of object creation.
Types of constructors:
1.default
2.parametarized
3.copy // it will copy the values of one object into another object.
Destructor:
it is also a special type of member function,which is
used to destroy the objects,which are allocated by the constructor
but java doesnt support it.java has garbage collector.
java has internelly one mechanisam called 'garbage collector'
to do destructor work.
