This photo was taken by my friend on June 17, 2011 during my trip to Jepara, Central Java, Indonesia.
This small Island called Pulau Panjang and can be reached with a local boat (around $1), which will take about 30min travel from Bandengan Beach, Jepara.
Well, there is not much to do in this island, but you can walk around the island in about 30 min, take some pictures of the island, go swimming, fishing, etc. Snorkeling is not really to recommend here, because there is no beautiful reef.
However, as its cheap to get here, it is worth to enjoy. ;-)