The Merak-Bakauheni ferry is probably the most popular. There are also ships between Jakarta and Singapore via the Indonesian island of Tanjung Pinang. There's no reason to fly around Java unless you want an aerial view of the island's spectacular volcanoes. There are a number of domestic airlines , including Garuda, the national carrier, Merpati, Sempati and Bouraq. It's essential to reconfirm your ticket since overbooking of flights is common.
Buses are the main form of inter-city transportation.
They range from slow, crowded, ordinary public buses to convenient, quick and comfortable luxury services. Small minibuses cover shorter routes, backroads and inner-city destinations. Java has a pretty good rail service running from one end of the island to the other. Choose your train carefully for comfort and speed. They range from cheap, squalid cattle trains to reasonably comfortable expresses.