17 Introduction of The Demo Levenshtein Distance Well known algorithm for measuring similarity of 2 strings. Required for comparing messages coming from other XMPP clients. Used in Apache Lucene (open source text search engine). – If S is "test“ and T is "test”, LD(S,T) = 0 // Coincident – If S is "test“ and T is "tes”, LD(S,T) = 1 // a bit different – If S is "test“ and T is "tst”, LD(S,T) = 1 – If S is "test“ and T is "te”, LD(S,T) = 2 // quite different url :http://en.wikibooks.org/wiki/Algorithm_Implementation/Strings/Leve nshtein_distance#Java