first off stealing oil..that cowboy guy was right? Jake didn't do anything about it? just found out that the other jake din't kill for money and that kittty is the daughter of Evelyn Mulwray and it kinda ends.. why did jake withhold the tape from the cops, why did the other jake want it? a fake reputation is all a man has.
I'll answer your question regarding the ending. When Jake (Keitel) kills himself and blows up the place it's assumed that an investigation will ensue and the oil will be discovered. Kitty/Katherine owns the rights to the minerals under the subdivision, hence the oil.
About the recording, Jake was implicated and was being accused to have "allowed" Jake (Keitel) to have murdered his partner so he wanted to figure it out for himself first. Most importantly, when he heard the name "Katherine Mulwray" he wanted to know how she was involved because he wanted to protect her. Everybody else wanted the recording to either prove Jake (Keitel)'s innocence or guilt.
Jan 25, 2011 the day it all started. Walk like an Egyptian or just protest like one!
right...in their own way, both Jakes (The Two Jakes) would end up looking out for Katherine. Jake Berman (Keitel) with the land and mineral rights, and Jake Gittes (Nicholson) by omitting Katherine's name in the tape recording.