Dr Russell Hanley asked about mangroves.

Here in Australia, particularly in Queensland, there are two main mangroves which are sometimes worked by beekeepers.  They may occur in your part of Java.  They are:-

Avicennia marina var. resinefera.  This flowers around February and can produce honey in some seasons.  Even though it flowers it does not necessarily produce honey.  It can be white in flower and not produce.  It has a taste all of its own and some people find it not to their liking.

Aegiceras corniculatum which flowers around October or November and can produce honey but can flower and not produce.  It has its own taste but is not as objectionable as the one above.  It is very light in colour and candies with a very fine grain.

The botanical names I have quoted above may not now be current but should be still listed as synonoms.

There are many other mangroves in the north of Australia but as there are no honey bees there, I cannot comment on how bees would work them.

Trevor Weatherhead
AUSTRALIA