COMException is a Java exception class that represents COM errors. It includes a getHRESULT method so that client code can examine the COM HRESULT value without parsing error message text.

COMException is declared as a subclass of IOException for the convenience of servlet and JSP writers. The standard servlet signature includes a "throws IOException" clause, enabling the servlet to not catch IOExceptions. By declaring COMException as a subclass of IOException, the servlet writers can dispense with the "catch (COMException)" clause if they want.