java - Is Exception Enrichment a viable pattern? -

i came across article jakob jenkov enrichable exceptions. idea!

i've been java developer 4 years, , still annoyed trying figure out sqlexcepions, ioexceptions, , random exceptions thrown third-party libraries. end putting thought when appropriate tho rethrow exception, or wrap 1 custom exception, if write custom exception, put it? in same package class i'm writing, or in central "exceptions" package? i've toyed declaring custom exceptions inner classes since seem pretty one-off.

anyways, jenkov's idea outlined here: http://tutorials.jenkov.com/java-exception-handling/exception-enrichment.html

using single enrichable exception outlines seems attractive me seems pretty handily side-step of frustrations. don't think i've ever seen used in of libraries i've used. there reason that? there major flaw approach i'm missing?

simple summary:

public class appexception extends exception{     public appexception(string errcode, string context, string usermessage, throwable t){}      public appexception(string, errcode, string context, string usermessage) {}      public void addinfo(string errcode, string context, string usermessage){} }  public class myapp {     public static void main(string [] args) {         myapp app = new myapp();              app.start(args[0], args[1]);             }      public void start(string username, string password) {         try {             user user = logincontroller.login(username, password);         } catch (appexception e) {             if (e.getcode().contains("incorrect_password")) {                 logger.warn(e.tostring(), e);                 // prompt user new password , try again.             } else {                 logger.error(e.tostring(), e);             }         } catch (exception e) {             logger.error("unexpected exception.", e);         }     } }  public class logincontroller {     public user login(string username, string password) {         try {             if (userdao.checkpassword(username, password)) {                 // build , return user object.             }         } catch (appexcption e) {             e.addinfo("login_failed", "logincontroller", "failed login");             throw e;         }     } }  public class userdao {     public boolean checkpassword(string username, string password) {         try {             // check password against db.              if (passwordiscorrect) {                 return true;             } else {                 throw new appexception("incorrect_password", "userdao", "password user " + username + " not correct.");             }         } catch (sqlexception e) {             throw new appexception("db_connection_err", "userdao", "can't connect database", e);         }     } } 

actual implementation of exception class available in jenkov's article. in above code example, if db unreachable error log like:

[login_failed, loggincontroller], [db_connection_err, userdao] [login_failed, loggincontroller]: failed login [db_connection_err, userdao]: can't connect database <<sqlexception stacktrace here>> 

but if incorrect password entered be:

[login_failed, loggincontroller], [incorrect_password, userdao] [login_failed, loggincontroller]: failed login [db_connection_err, userdao]: password user [passed in username] not correct. 

i'd add enum or error codes make selective handling easier, , ensure unique. error message gives clear concise view of when wrong, , it's easy add additional information error climes call stack developer able recreate error.

so repeat question. why isn't used more widely? there major flaw in approach i'm missing?