Casting

Casting

Integer Hierarchy

  1. long
  2. int
  3. short
  4. char
  5. byte

Floating Hierarchy 

  1. double
  2. float
According to the above sequence the data types that are in the highest point have the highest power than lowers.

Upcasting

We can understand upcasting simply as giving the subclass object to the super class variable.
In upcasting we cannot access higher types by lower types.
But lower types can be accessed by higher types.

Downcasting

Converting the sub class object added to the super class variable back into sub class variable.
This is simply giving the super class variable to the sub class variable.
For this,sub class object is used as parameter.





Comments

Post a Comment

Popular posts from this blog

Variable and Method types in JAVA

Image
  Variable types..... 1) Local variables/method local they are inside a method. eg :- class A {         void a () {         String x ;         }           } 2) Instance variables the variables inside a class. but cannot be inside a method. eg :- class B {          String x ;         } 3) Static variables/class variables Static variables must be in a class. but it cannot be inside a method. eg :- class A {          static String x ;         }            Method types..... 1) Pre - defined methods. - pre built methods in JDK - public static  void main (String[]args) {} - print (); - get (); - set (); 2) User - defined methods. - methods created by the user. -2 types static methods - static void draw () {} non static nethods - void eat () {} / void write () {}   ...
Read more

Polymorphism

Image
 Polymorphism The process of calling the sub class methods by using the super class reference with the help of Overriding,Inheritance and Casting concepts. After we override a method of a super class inside a subclass,we can do casting and then through the super class reference,we can call the sub class method. We can perform many tasks in different classes by using this concept. This simply means "Many Forms". Assume that there is a company.It stores Biscuits and Cakes seperately.For that we have to develop a system to store them in the correct manner. As Java is a compiler,it executes its codes line by line. Now if we have either cakes or biscuits,the should have to store in their correct places. So for that we can use polymorphism with casting,inheritance and method overriding concepts. We can create seperate objects for those sub classes. Super class is called and then the sub class is executed. This is a simple idea about how we can use polymorphism practically. Let us d...
Read more