It was an awesome relic structure in the midst of Jakarta and in the vicinity of the 6th Biggest Mosque as well. Amazing structure inside out. Great place to visit. Just a warning though, be very cautious about scams.
Jakarta has a wide range of very mixed religious buildings, ranging from very early mosques to Chinese Catholic churches that look like Buddhist temples.
In Purwokerto, central Java, there is a very interesting Chinese mosque.
As with the church, first look suggests a temple, but closer inspection sees Islamic influences.
As a note, the Dutch kicked all the Chinese out of Batavia, the ones they didn't murder, so the area close by, now known as Glodok, became the Chinatown.
The second president, Surharto, banned the Chinese language, Chinese names and pretty much everything else Chinese as part of his anti communist purge.
That pretty much destroyed outward signs of Chinese influence but that's returned since he was removed.
As with any banned culture, it didn't die, more was kept alive secretly.