This paper aims at designing communication strategies for parallel and distributed Java applications to obtain higher degrees of performance on clusters. Several specific approaches exist to increase the efficiency of Java communications, specially of high level APIs like RMI, although their applicability is relatively limited on clusters, since the development of high performance solutions on clusters usually involves the use of the basic Java Socket interface. This paper examines the current outlook of Java Socket optimisations involving both native and Java side issues in order to make a design proposal named Java Fast Sockets. We have accomplished a thorough analysis of the effects of the suggested configurations and implementations on our Scalable Coherent Interface (SCI) testbed cluster. This evaluation has demonstrated that Java communication performance on clusters can compete with native performance.