What you have to deal with when you work with AppDynamics – or other APM tools

For many years now I have been working with Application Performance Management (APM) tools in the Java realm. Compared to other performance analyzing tools as for example profilers, APM tools are monitoring as well as analyzing tools. They provide a better overview over distributed applications and can offer a direct connection between user actions, users’ performance experiences and technical processes.
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Dr. Raymond Georg Snatzke

The Machinery behind Machine Learning – Part 2

Machine Learning is one of the hottest topic on the web. But how do machines learn? And do they learn at all? The answer in most cases is: Machines do not learn, they optimize.
This is part 2 of the series, and after all the preparation it definitely is time to do the first numerical experiments. You can find the respective R code here.

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Stefan Kühn

The Scala Type System: Parameterized Types and Variances, Part 3

With the help of co- and contravariance annotations in Scala you can derive relationships between parameterized classes from their type parameters. The compiler checks with specific rules how the type parameters are used in a generic class. In this, he checks if all uses of type parameters are legal, i.e. if the generic class is type safe.

Generic classes and co-/contravariant annotations are powerful tools that can be used on plentiful occasions when designing a class and while coding. However, where does it really makes sense to use these tools? This blog post presents my insights and my current opinion on this topic.

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Andreas Schroeder