This library allows access to graphs of Java objects by path-like strings. As a short example, suppose you have the following:

class A { String s; }
class B { A x; }

Then, given an instance of class B, the path "/x/s" would provide access to the string s.

Early-nulls (if x were null) are also supported (as in JSP's Expression Language), but so is automatic graph construction. In such a case, a new instances of A would have been assigned to x to access the (still null) string s.