Is there a distributed version control system (like git or Mercurial) that can be used as an embedded library in Java applications (to implement versioned and synchronizable sto
I do not know of any pure Java solutions. But, check out http://javagit.sourceforge.net/ you can use it to connect to a git repository with Java.
There is a pure Java library, SVN Kit for interacting with Subversion
@Josh Moore's reply led me to JGit, which seems to be a competitor to JavaGit. JGit is pure Java and licensed under BSD.
Some further digging unearthed HgKit, which aims to implement Mercurial in Java. It is still pre-alpha and GPLed.