Error: it is deviation from logic,syntax or execution.
there r 3 types of errors
syntactical error: it is deviation from syntax of program
logical error: it is deviation from logic of the program.
executional error: this occurs during executing the program.
Deffect: when the error is discovered by the tester then it 
is called deffect.
bug:if the developer accepts the deffect then it is called 
bug.

Bug: it is inconsistancy netween Functional Requirement and 
actual implementation. If something is already documented 
to be implemented and implementation is not consistant as 
per requirement then its a BUG.

Defect: If something is happening with the functionality 
that is not mentioned in any document to be followed during 
implementation or testing then its a defect.
Like if we double click on any Folder existing on the root 
node and get an Internal Error or System Crash message then 
its a Defect.

Hai friendz i am rajendra,

I would like to give simple and easy answer for this 
question,
Error -A Fault in the program leads to error in program  
       exection.
Defect-If the error caught by tester then it  is  called
       as defect.
Bug -  If the defect is accepted by the development people
       then it is called as Bug.

          Fault---->Error---->Defect---->Bug
Error may be generated due to  syntax or symantic fault.

Different types of error are 
         1.syntax errors
         2.symantic errors
         3.Logical errors
         4.Runtime errors...etc

All athe above errors will be occured during white box 
testing of the application/product.

In BlackBox testing main defects are
         Requirement missing or
         Wrongly interpreted requiremets,
         Misoperation of fuctionalities...etc.

ok byeeee
 rajendra_penumalli@yahoo.com
09885162742
hyderabad

When there is a mistake in programming it is a ERROR
The error noticed/found by the tester is a DEFECT
When the defect is agreed by the programmer also then it is
a BUG.

Error is an fault in the program (eg: syntax error).

Defect is an mis-match of Actal result and Expected result.

If the defect is accepted by the developer, then its called 
as Bug.

bug: developer find the bug.before give the product to the 
test engineer....
defect: test engineer find this.after coming the product 
they check e.r not equal to a.r . this s called defect
error: customer find the error. after delievery the product 
to the customer they only find the error.

Simply any thing find by tester its defect, when the 
developer accepts the defect its bug. Any thing found 
faulty ie fault is an error.

Fault--> Error--> Defect--> Bug   

Pls correct me if it not correct.

error : A mistake in a coding is called error.

defect: due to errors in a coding testing engineers are 
getting mismatches in the app. build it is called as defect 
or issue.


bug: these defects or issues are accepted by developers to 
be solve then it is called as bug

The Error is the wrong in the code, which causes runtime 
errors or Page can not display errors or any syntax errors. 

The Defect is the improper behaviour of the system or the 
application, like if the button (Submit or Save) is not 
working.

Bug is if the system doesnot meet the client requirement.

Thx
Satya

Defect : From Producer Point of View , Any Requirement that 
is Missed out from that it was agreed to incorporate into 
product . This can be found during Verification , means 
Reviews  and not in validation like Testing ..
eg. I design a car as per the need of Middle Segment and i 
don't miss out what ever i have planned out ..

From Consumer Point of view , Anything that causes 
dissatisfacti0on ,irrespective of Requiremnts were fully 
incorporated or not ...
My customer finds that there in no Antilock system ..From 
my point , I have produced a DEFECT - fREE Product ,but it 
is still defective from customer point


Bug : When an unexpected thing happens from what is 
Expected , it is Bug .It happens in Testing  and in all 
validation techniques..
While testing the car , the car has to withstand 100 N,but 
it withstands only 80 N Force ..Its a bug !

Error : Syntax ,logical

Error : In a program if there is any statement logically 
incorredt then it is called as an error

A mistake or fault done in the coding that makes error to
lead the program execution is called error..

If the error caught by tester then it  is  called as defect
or simply we can say the mismatch between actual and
expected result...

If the defect is accepted by the development people then it
is called as Bug.