I can give u a guide:
1. Find normal buffer in java(there are few as far as i know)
2. Create button that will open main scheme edit page
3. In main scheme edit page i think u should have: Add new scheme button(text box + button), list of existing schemes with Edit, Delete and Set Main Scheme buttons
4. Create class of scheme - vars: String name, boolean main, List<L2Skill> buffs.
5. After some1 click on create scheme button, it should check if name is correct(and if there arent any schemes with same name) and then add this scheme to player's List of schemes.
6. edit scheme button should give u list of all buffs(that scheme doesnt have) with Add button near them. Also u should add Remove Buffs button.
7. Add button should just add L2Skill to buffs list.
8. Remove buffs button should show u list of all buffs that scheme already with Remove button near it
9. Remove butto nshould remove L2Skill from buffs list.
10. Delete scheme button should remove scheme from the list of player schemes
11. In main page of the buffer there should be button which will give u buffs from the Main Scheme after getting clicked.
12. On player log out, it should save schemes to database, i suggest such table: int char_id, String scheme_name, int main_scheme(1 or 0), int skill_id, int skill_level
13. On player log in, it should read all schemes of the player and add them on the list.