Java Internal Databases

I wish to write an application which will be required to store large quantities of information which needs to be kept on the same computer as the application and does not require anything to be installed on the computer first.



Therefore I was wondering if there was a form of database that could be run using java so that it can be self contained.  I do need this data to be stored throughout uses and comptuer shutdowns.



I also need to be able to send copies of it over a network to other computers quickly as there will be a central computer running a main program, and then several others running a slave program which will update the database once per day, and possibly request certain data during the day.



Would anyone here know a sutible database type structure that i can use for this?