Apache Lucene Fundamentals Tutorial

Course Overview Apache Lucene is a free/open source information retrieval software library, which provides Java-based indexing and search technology, as well as spellchecking, hit highlighting and advanced analysis/tokenization capabilities. Lucene is a high-performance, full-featured text search engine library written entirely in Java. It is a technology suitable for nearly any application that requires full-text search, especially cross-platform. In this course, ...

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Introductory NoSQL stuff

While some of you might be NoSQL gurus, there is often a lack of solid knowledge about NoSQL in general and some common myths as well. Specifically, topics like NoSQL applicability/use cases and its comparison (fair and unfair) against relational databases are often driven by incomplete knowledge. I do not claim to be an expert in the NoSQL domain, but ...

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What is promotion rate?

I do believe you are familiar with the Peter principle. In general, the principle is an observation that promotions can and will lead to a situation where the promoted person is no longer qualified for the job. For the JVM the similar problem exists. Promoting objects too fast can have significant impact to performance. In this post we open up ...

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Integrating JPA Hibernate with OptaPlanner

We’ve been improving the integration of OptaPlanner with the rest of JEE, so it’s easier to build end user applications that just work. Let’s take a look at the improved JPA Hibernate integration. The basics Both JPA Hibernate and OptaPlanner work on POJO’s (Plain Old Java Objects), so just add some JPA annotations on your domain objects to persist them ...

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Stop empowering people – End disempowerment!

In the last two posts I’ve discussed some problems with of self-organizing teams and highlighted the need to be clearer about what is actually meant when talking of, that is naming, self-organizing teams. At a minimum the labels need clear definition (I suggested some definitions and I hope someone knows some better ones.) I went further and I called for ...

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Spark 101: What Is It, What It Does, and Why It Matters

Recently, a new name has entered many of the conversations about big data. Some people see the popular newcomer Apache Spark™ as a more accessible and more powerful replacement for Hadoop, the original technology of choice for big data. Others recognize Spark as a powerful complement to Hadoop and other technologies, with its own set of strengths, quirks and limitations. ...

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Running OpenShift Origin on Windows

OpenShift is the most interesting PaaS offering these days for me. Not only because it is part of the Red Hat family of products, but because it holds everything I expect from a modern PaaS. It supports image based deployments (with Docker-Images), abstracts operational complexity (e.g. networking, storage and health checks) and greatly supports DevOps with an integrated tooling stack. ...

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Writing an Event-Sourced CQRS Read Model

java-interview-questions-answers

Discussions about event sourcing and CQRS seem to usually focus on the overall system architecture or various flavors of domain-driven design in CQRS context. However, the read models are often neglected, even though there are some interesting considerations on this side as well. In this post we’re going to present a sample implementation of populating a view model by consuming ...

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