Difference between System exceptions and Application exceptions

In ASP.NET all exception derives from Exception which is Base class. Exceptions can be generated programmatically or can be generated by system. Application Exception serves as the base class for all applicationspecific exception classes. It derives from Exception but does not provide any extended functionality. You should derive your custom application exceptions from Application Exception. Application exception is used when we want to define user defined
exception, while system exception is all which is defined by .NET.