Davide Ancona		Mirko Viroli

Guest Editorial

Dear Readers,

continuing the tradition started with OOPS (Object-Oriented Programming Languages) at SAC (Symposium on Applied Computing) 2004, this special issue hosts extended versions of papers already published in the ACM proceedings of SAC 2006.

The OOPS track promotes extensions and enhancements to the maintream object-oriented languages and standard systems, and solicits contributions on design, theoretical, and architectural aspects covering a large spectrum of topics, including, programming abstractions, advanced type mechanisms and type safety, multi-paradigm features, language features in support of open systems, aspectoriented and component-based programming, reflection, and program structuring and modularity.

At OOPS 2006 eight full papers and one poster were accepted for publication, with an acceptance rate of 42 %; between them, five papers were selected and their authors were invited to submit a journal version.

The five papers underwent a rigorous review process, including two rounds of revision; each paper was referred by two expert reviewers to ensure the good quality of the papers, and the presence of extra contribution with respect to the corresponding conference papers.

Last but not least, we would like to thank all people who made possible the publication of this issue.

The fourth edition of OOPS special track at SAC 2007 will be held in Seoul, Korea, on March 11 - 15, 2007.