Obscure Indonesian fruit facts, anyone?

I'll post this query in the ethnic section because the fruit in question is commonly eaten in Indonesia. But I think this is a really obscure matter - if anybody (except maybe Eggy, who knows so much about Asian food) can help I will be pleasantly surprised.

Anyway, here goes: there is a fruit here called "jambu," and since my son is crazy about it I would like to know something about the nutritional content, whether the seeds are poisonous, and whether anyone has any recipes using this fruit. In English it is called a "rose apple," but I believe that a different fruit may also be called rose apple. Jambu are somewhat bell-shaped and are about the size of a plum. Their color varies from pale greenish-white to pale pink to red. The taste and texture are rather like that of an apple that has had most of the juice and flavor sucked out. Truly, they are not particularly delicious! I am surprised that my son likes them, but it is probably because we have a gigantic jambu tree in our yard and are currently being bombarded by falling jambu, a phenomenon he finds pretty interesting.

I found some horticultural info on the Net but it did not discuss the nutritional value. I'd assume it is minimal because they lack flavor, but papayas are also tasteless and they are very nutritious, so that isn't necessarily a guide. The horticultural info said that the seeds are "considered to be" poisonous. I doubt they are particularly dangerous since I have a whole houseful of Indonesians who are happy to let my son play with the fruit, but still... The Net stuff also said that the fruit is usually used in chutneys, etc. in combination with stronger-flavored fruits.

Comments anyone?