Some scipts, such as those used in India, use Unicode composition to form complex characters. To type compound characters in these scripts you first type the base character, and then the modifier character. This matches Unicode composition, but is reversed from the Latin dead key processing.
Java supplies a complete set of keyboards for the scripts used in India as a set of IME's. These can be accessed by selecting the IME popup from the System menu (in the upper left corner of the Window). On Linux, you need to set the popup hotkey to use these IME's.