Define the type casting?, JAVA Programming

 

Type casting defines treating a variable of one type as though it is another type.

When up casting primitives as given below from left to right, automatic conversion happens. But if you derive from right to left, explicit casting or down casting is needed. Casting in Java is safer and easier than in C or other languages that allow arbitrary casting. Java only lets casts happen when they build sense, such as a cast between a float and an int. However you can't cast between a String and an int.

Byte, short, int, long, float, and double

int i = 5;

long j = i;         //Right. Implicit casting or up casting

byte b1 = i;      //Wrong casting. Compile time error "Type Mismatch".

byte b2 = (byte) i ;       //Right. Explicit casting or Down casting is required.

When it needs to object references you may always cast from a subclass to a superclass because a subclass object is also a superclass instance. You may cast an object implicitly to a super class type. If that were not the case polymorphism couldn't be possible.

 

 

 

2281_Untitled.png

 

You can cast down the hierarchy as well but you have to explicitly write the cast and the object must be a legitimate instance of the class you are casting to. The ClassCastException is given to indicate that code has tried to cast an object to a subclass of which it is not an instance of that class. If you are using J2SE 5.0 then "generics" will remove the need for casting otherwise you may deal with the problem of incorrect casting in two ways:

1.      Use the exception handling process to catch ClassCastException.

2.      Use the instance of statement to protect against incorrect casting.

 

Posted Date: 7/25/2012 2:53:54 AM | Location : United States







Related Discussions:- Define the type casting?, Assignment Help, Ask Question on Define the type casting?, Get Answer, Expert's Help, Define the type casting? Discussions

Write discussion on Define the type casting?
Your posts are moderated
Related Questions
What is output of the following JavaScript code? Str="Virtual University of Pakistan"; document.write(str.substring(5,str.length)) ;

Staging areas that have messages those have been sent and are waiting to be read. Note that, contrary to what the name queue suggests, messages don't have to be delivered in the or

Did Java support hybrid inheritance?

Object Relational Mapping , its a tool for transaction management that requires to be integrated with Spring, Struts etc.Eg : Hibernate, i Batis,JDO etc

Java expert with tomcat tuning experience needed Project Description: Want a Java expert to fix memory issues with tomcat. I need School java project - Threads Programm

examples of 2D arrays

How can you define a readable program? A program that is easy to read & understand also easy to maintain and enhance. Readability is the ease in that text can be read and under

Develop E-Commerce Website I need an E-Commerce website for my furniture shop which requires to an online store to buy products online. So, Skills required: HTML, Java, Gr

Annotation or Attribute oriented programming There are two types of code generation processes. Passive code generation: is template driven . Input process are used in mo

Business Objects represent the data client. They are the objects that need access to the datasource to obtain and store data. Data Access Objects abstract the relying data access i