An exception is an error that happens during the execution of a program. Exceptions are known to non-programmers as instances that do not conform to a general rule. The name "exception" in computer science has this meaning as well: It implies that the problem (the exception) doesn't occur frequently, i.e. the exception is the "exception to the rule". Exception handling is a construct in some programming languages to handle or deal with errors automatically. Many programming languages like C++, Objective-C, PHP, Java, Ruby, Python, and many others have built-in support for exception handling.
Error handling is generally resolved by saving the state of execution at the moment the error occurred and interrupting the normal flow of the program to execute a special function or piece of code, which is known as the exception handler. Depending on the kind of error ("division by zero", "file open error" and so on) which had occurred, the error handler can "fix" the problem and the programm can be continued afterwards with the previously saved data.
