constructor and constructor myths

-
Constructor:-
             In java programming language all the no static variables that are defined in the class are known as instance variable of the class and in java every thing is represented as an object so that when a user creates a class want to use the functions and properties of that class then that person should have to creates a object of that class. Now the constructor must be used to create the object of the class. The main functioning of the constructor is to provide the Reference ID of the constructor generated by JVM.
Some Basic Rules to declare the constructor:-
1. constructor name should be same as the class name.
2. constructor return type does not specified by the programmer.

Syntax with example:-
    class ABC
     {
            ABC()
            {
            }
     }

constructor type:-
1. default
2. parameterized

1. default:-
           constructor with the empty parameter list is called a default constructor.
2. parameterized:-
           constructor with the parameter is called parameterized constructor.

 Note:- constructor does not have the programmer defined return type does not mean that constructor do not have return type "JVM returns the reference ID of the constructor through the constructor." that means constructor is a non-static method whose return type is specified by the JVM. 
              Because of we writing the code for creating the object of any class suppose we have a class A then the object creation statement of this class is some thing like-
                   A obj=new A();
      in the statement we call constructor and place it in the right side of the assignment operator and in the programming all the statement that are at the right side of the assignment operator must return some value. so that's clear that constructor return some value that we store in the reference variable "obj" of A.
       so that the statement that "a constructor does not have any return value is partially correct"
I explain the javap tool and the how to create the constructor and what happen if we don't place any constructor in the class in the video whose link is following- 
                                          https://youtu.be/mx__f1hkWfU

Comments

Post a Comment

Popular posts from this blog

Reflection in java

-
Reflection:-         Reflection is the way to recognize any class at the runtime even if their name is found at runtime. If at the development time the class name is not known by the developer then we cann't use that class without reflection.        The use of class can be load that class, to create the object of that class, invocation of the methods. By Reflection the details of the class can also be obtained such as list of their methods, list of constructors, list of the fields, name of parent class and list of implemented interfaces. Note:- Reflection is meta data of class.         According to the Reflection each and every class and members of that class represented by the objects these objects are known as the reflected object or meta object.         Through the reflection in any java program we can obtained the meta data. java.lang.Class:-               ...
Read more

Input/Output Stream in java

-
Image
input/output are the two major processes in any application development. java follows the stream based input/output. A stream is a channel through which data will be transmitted. example:- Advantages of stream based I/O over Normal I/O:- Abstraction:-  Streams hides the internal complexity of I/O. Flexibility:- Streams provides a flexibility to be used in the program according to the requirement. Efficiency:-  Streams also performs the additional operations onto the data so stream based I/O always be effective over the normal I/O.                   Their are two types of streams in java- 1:- Byte Stream:- it follows the 8 bit sequence. 2:- Character Stream:- it follows the 16 bit sequence.        java.io package provides classes known as Stream classes whose objects are considered as the stream in the java applications.         InputStream & OutputStr...
Read more

Inter-Thread communication

-
Inter-Thread communication :-                            -synchronized method/block will provides an unordered mutual exclusivity b/w the thread to access the objects. Thats means if one thread start the execution of synchronized method then their is no certain time for the completion of method, upto that time the other thread have to wait. To overcome this problem we use the concept of inter Thread communication.                                     In case of inter Thread communication the threads are capable to access the synchronized objects in the mutually exclusive manner in the ordered way that means any thread can release the lock during the execution of the synchronized method or block and moved into the waiting state.         "java.lang.Object class" this class provides the following methods for ...
Read more