This is a parser in Java for Lisp S-expressions. An S-expression or sexp (for symbolic expression) is a convention for representing data using parentheses.
RefLisp is a small Lisp interpreter written in C++. It has:
an built-in web server, Wiki, LISP server pages, SQL Databases, XML parser, MD5 hashing, regular expressions, reference counting and mark-sweep garbage collection, GPL.