John Zhou

Boy, that sucks.
remove from item .... /item.

strange, in above email, I typed remove from \<Item\> ...\</Item\> become ......, I guess it is the angled parenthesis escape.

Here is how you can remove a jdbc driver entry.
1) close jdeveloper.
2) edit ~/jdevhome/system9.0.3.1.1107/settings.xml, find the driver name and remove from <Item> ......</Item>, save your changes and exit.
3) start jdeveloper, you will see the driver name is no longer there.
Do not edit settings.xml with jdeveloper opened, because jdeveloper will save all settings when you close it.