pvDataJava is the Java implementation of pvData, which defines and implements an efficent way to store, access, and transmit memory resident structured data

pvDataJava is one of a related set of products:

pvData
pvData (Process Variable Data) defines and implements an efficent way to store, access, and transmit memory resident structured data
pvAccess
pvAccess is network support for transmitting pvData.
pvIOC
A pvIOC is a network accessable smart real time database. The database consists of memory resident records. Each record has a name that is uniquie within the local area network and contains a top level pvData structure. Each field of a record can optionally have support code attached to it. The support is called when a request is made to process the record. The support code is what makes the record "smart". A pvAccess server is provided so that the records can be accesed via the network.

See documentation/pvDataJava.html for a more complete overview.