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JAXB and Root Elements

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@XmlRootElement is an annotation that people are used to using with JAXB (JSR-222). It’s purpose is to uniquely associate a root element with a class. Since JAXB classes map to complex types, it is possible for a class to correspond to multiple root elements. In this case @XmlRootElement can not be used and people start getting a bit confused. In ...

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Java Thread at RUNNABLE state is not really running

Recently, I was doing an analysis/tuning on a Java application server installation in order to identify the bottlenecks and fix them. The most common action in such procedure (tuning) is to retrieve many Thread dumps, when system is on load. Please have in mind that heavy load (for some cases) may have side effects that they may lead us to ...

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Exception: java lang AbstractMethodError

This java.lang.AbstractMethodError is usually thrown when we try to invoke the abstract method.Generally this error is identified at the compile time itself,if this error is thrown at run-time then the class must be incompatibly(not compatible with preexisting classes) changed.Hence it is a sub class of IncompatibleClassChange Error. We know that an abstract method cannot be invoked and if we try ...

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How to build a DIY Service Repository

Every Jedi faces the moment in their life when their Lightsaber simply fails to perform as expected and he or she has bite the bullet and build a better one. Not being a Jedi I clearly have no use for a Lightsaber, but I did have a recurring irritation in the form of the service registries and repositories. These tools ...

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Groovy DSL – A Simple Example

Domain Specific Languages (DSLs) have become a valuable part of the Groovy idiom. DSLs are used in native Groovy builders, Grails and GORM, and testing frameworks. To a developer, DSLs are consumable and understandable, which makes implementation more fluid as compared to traditional programming. But how is a DSL implemented? How does it work behind the scenes? This article will ...

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Java Exception: java lang NoSuchMethodError

If you have a look at the error message java.lang.NoSuchMethodError you may understand that the Java Virtual Machine is trying to indicate us that the method you invoked is not available in the class or in an interface. You could have also seen this error thrown when executing a class that has no public static void main() method.To know the ...

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Memory Access Patterns Are Important

In high-performance computing it is often said that the cost of a cache-miss is the largest performance penalty for an algorithm. For many years the increase in speed of our processors has greatly outstripped latency gains to main-memory. Bandwidth to main-memory has greatly increased via wider, and multi-channel, buses however the latency has not significantly reduced. To hide this latency ...

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Top 5 SOA gotchas and how to avoid them

After 5 years of designing and building award winning service oriented architectures, I thought I’d share my top 5 SOA gotcha’s and some general hints on how you can avoid them in your SOA programme. 1. Failure to recognise that Service-Orientation is about design (and not about technology). Service-orientation is to web services what object orientation is to Java, C# ...

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Oracle Public Cloud Java Service with NetBeans in Early Access

Who expected that to happen: Oracle is working on a public cloud offering and the signs of the approaching official launch are there. Nearly a year after the official announcement I was invited to join the so called “Early Access” program to test-drive the new service and give feedback. Thanks to Reza Shafii who is the product manager in charge ...

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