Above mentioned Examples can not prevented but a workaround is possible,Simply provide code to detect that file is exist or not before doing any other operation on it(its make no sense to work on non existent entity)
Exceptions may occur due to poorly written code,i.e, a method may try to access nonexistent element this cause occur due to poor coded to access Array. This kind of exceptions can be prevented by correcting the code.
An Exception might occur and can not prevented and there is no workaround for such Exceptions. for example,virtual machine in Java runs out of memory or it could not find a particular class file. This is exception is kind of ERROR. This must be corrected otherwise app. have to be terminate.
Error Code
Error codes are one of the ways to represent error in source code. For example, a method can return true on successful execution or return false on failure.Many developers used error codes method to handle exception.if(//file exist)
{
// all code
}
else
{
//show msg to user that file is not found
}
in above example else part demonstrate Error Code.
Error codes is easy to ignore and many developers ignore it,for example, A programmer may ignore false return value that file does not exist but proceed to work on it! nonsense.
Thats Why Object Code new approach to handle exceptions developed
Object Code
This approach is Object Based. an Object is created when exception is thrown, this object includes information about what error led to exceptions.This detail is latter used to provide workaround.Error codes are less useful then Objects.For example, Error codes return false or an non-zero integer on failure but what is meant by false? or integer? but object is more useful for providing Workaround for exception thrown.Error codes can't provide detail description about exception.
