TNS-12519: TNS:no appropriate service handler found in Oracle10g XE

this is a bug on how OracleXE monitors processes.

database didn't register with the listener and that the processes parameter needed to be increased. So do the following two things to fix this issue:

SQL> alter system set processes=500 scope=spfile;

SQL> alter system register;

reference:

1.http://www.franklinfaces.com/Topic107-55-1.aspx
2.http://en.newinstance.it/2007/06/01/ora-12519-tnsno-appropriate-service-handler-found/