The Eternity 2 (E2) puzzle has attracted the attention of puzzle fanatics, computer programmers, and mathematicians for many reasons, not the least of which is the $2 million prize for being the first to solve it. E2 is an edge-matching puzzle with 256 pieces. The general class of edge-matching puzzles is known to be NP-Complete, but it is unknown if there are aspects of E2 that can be exploited to make it tractable. In the spirit of cooperation, a few people have made their automated solvers available online, and I have provided an overview and back-of-the-napkin analysis of two of them. (more…)

Optimizing J2EE applications is hard. Even if all of your algorithms have been analyzed in big-O notation and finely tuned, you can have abysmal performance due to a poorly configured environment. J2EE applications depend on many lower layers which all must be properly optimized in order to give good overall performance. This page gives a checklist of optimization tips organized by layer. It includes optimizations for the HTTP Server, Application Server, Java frameworks, database, and the application itself. This page isn’t intended to be a comprehensive optimization guide; it is a checklist of the most effective optimizations I have found that can be applied in most situations. This checklist is a good place to start before more focused optimizations - and you may even find that nothing more is required.
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Apache Axis is an implementation of the SOAP protocol. It is a framework for constructing SOAP clients and servers. A Java client application is able to use a Web Service by calling Java stub classes created from WSDL files. These WSDL files are made availible by the SOAP server application. As an example, we will go through the process of creating a jar file from WSDLs using the Yahoo’s Enterprise Web Services (EWS). The EWS platform makes Yahoo’s Search Marketing API available. (more…)