What is difference between Error, Bug, Defect, Exception, Fault, Failure and Crash?

Hi Friends,

I’ll try to explain all these term with an example as per my better understanding:

Error: A human mistake or issue occurred in program before or during Compilation of program.

Ex.

1.     If (a!=b)

2.     {

3.     c = a/b(;)

4.     }

If programmer missed the semicolon at the end of 3rd line of code and tries to compile, then an error message is occurred. This type of mistake called ERROR.

Bug: When an issue, unexpected result or deviation in actual functionality is found out by an Author (who wrote the code) after compilation of program and during any testing phase (At during development, Beta version or at production) is called Bug.

Ex. Author used the variable ‘d’ instead of variable ‘b’ or use divide symbol intend  of plus symbol, due to this there is no compilation error is occurred but it produce some unaccepted result.

Defects: When an issue, unexpected result or deviation in actual functionality is found out by a moderator (Not an Author of code) during any phase (At during development, Beta version or at production sites) of testing is called Defect.

Ex. Author used the variable ‘d’ instead of variable ‘b’ or use divide symbol instead of plus symbol, due to this there is no compilation error is occurred but it produce some unaccepted result but here issue is found out by Moderator.

Exception: An unhandled error is occurred at run time of program.

After compilation of program, when an unhandled error is occurred during any phase of testing (found out by Author or Moderator) is called EXCEPTION.

Ex. There is no error is generated during compilation of program but at run time it through an exception for b=0.

Fault: it is a state during testing, which indicate deviation from actual functionality.

Ex. In this example, Author used the ‘b’ instead of‘d’, this state when we got a deviation from actual result. This state is called Fault.

Failure: It is a state which rose due to a fault and affected a single part of functionality.

Ex. Due to this Fault state, any other single line code or single module is affected, this state is called Failure.

Crash: It is a state which rose due to a fault and affected to multiple functionality or a whole module or whole application.

Ex. Due to this Fault state, if any other multiple modules is affected, this state is called Failure.