It would help if you could also show us a picture of the whole tree. I never heard of your tree (Jambolan, Java plum, a number of other common names, Eugenia spp ) so I looked it up. I discovered you posted your question on several other forums and I also found this:
I have 1.5y old jambolan bonsai I need to know that is it important to cut all leaves those are half brown? if yes 70% of my bonsai leaves are half brown??
Post iskhan on Tue Jul 24, 2012
9:17 am at internet bonsai club: IBC Forum
That was a couple years ago. Is that the same tree? What did you do then? You didn't really get a response.
I also saw where you posted here:
https://www.helpfulgardener.com/forum/vi ... hp?t=27074
in 2010 about being "interested" in jambolan bonsai. Don't know if you actually had one at that time.
and in June 2010
you posted this
Your suggestion required regarding bonsai soil:
I am using 40% sand and 60% Compost for my Almond,Jambolan and Apricot bonsai is it OK?
What kind of fertilizer I use for them and when?
In fact pretty much everything I found on the internet about this tree was you....
You obviously have way more experience with it than anyone here, so why don't you tell us more of your history with it, what has worked, what hasn't, what you have learned. Is this all the same tree you have had since 2010 or have you gone through several of them?