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Core Java

Java 7: How to write really fast Java code

When I first wrote this blog my intention was to introduce you to a class ThreadLocalRandom which is new in Java 7 to generate random numbers. I have analyzed the performance of ThreadLocalRandom in a series of micro-benchmarks to find out how it performs in a single threaded environment. The results were relatively surprising: although the code is very similar, ...

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The Wizard Design Pattern

We all love wizards…. (Software wizards I mean). We are always happy to jump on those ”Next” buttons like we were dancing the funky chicken on our… well you get the point. So today we bring you your beloved wizard into your coding experience. Let’s jump right into an example. Say you want to design a ConservativePerson class. import java.util.List; ...

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Java 7 – The NIO File Revolution

Java 7 (“Project Coin”) has been out since July of last year. The additions with this release are useful, for example Try with resources – having closable resources handled automatically from try blocks, Strings in switch statements, multicatch for Exceptions and the ‘<>‘ operator for working with generics. The addition that everyone was anticipating the most, closures, has been deferred ...

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XML parsing using SaxParser with complete code

SAX parser use callback function (org.xml.sax.helpers.DefaultHandler) to informs clients of the XML document structure. You should extend DefaultHandler and override few methods to achieve xml parsing. The methods to override are startDocument() and endDocument() – Method called at the start and end of an XML document.  startElement() and endElement() – Method called at the start and end of a document ...

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if – else coding style best practices

The following post is going to be an advanced curly-braces discussion with no right or wrong answer, just more “matter of taste”. It is about whether to put “else” (and other keywords, such as “catch”, “finally”) on a new line or not.             Some may write if (something) { doIt(); } else { dontDoIt(); } ...

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Practical Garbage Collection, part 1 – Introduction

This is the first part of a series of blog posts I intend to write, whose aim will be to explain how garbage collection works in the real world (in particular, with the JVM). I will cover some theory that I believe is necessary to understand garbage collection enough for practical purposes, but will keep it to a minimum. The ...

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Understanding Java Weak References

I could not pay attention to the blog in the recent times and first and foremost I must apologize for not staying in touch with you all in the world of technology. I recently stumbled upon the java.lang.ref package which was available since Java 1.2 but ironically i got to know about it just a few days back. Going through ...

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TestNG or JUnit

For many years now, I have always found myself going back to TestNG whenever it comes to doing Unit Testing with Java Code. Everytime, I picked up TestNG, people have asked me why do I go over to TestNG especially with JUnit is provided by the default development environment like Eclipse or Maven. Continuing the same battle, yesterday I started ...

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Java Annotations & A Real World Spring Example

An “annotation” is a type of programming language definition and used as a “marker”. They can be thought as comment lines which programming language engine can understand. They don’t directly affect program execution but affect indirecly if wanted. Definition An annotation is defined with @interface keyword and is similar with an interface. It has attributes which are defined like interface ...

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