Executing procedures from the dbms_java Oracle PL/SQL package may result in a strange IdNotFoundException like:
ORA-29532: Java call terminated by uncaught Java exception: oracle.aurora.vm.IdNotFoundException: user : user or role id does not exist
This is very common when granting java.io.FilePermission:
call dbms_java.grant_permission('user', 'java.io.FilePermission', 'C:/MyFolder/ora-pgp-1.1.0.jar', 'read');
If you experience such error try changing the user(schema) name to Uppercase.