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String deduplication feature (from Java 8 update 20)
by Mikhail Vorontsov This article will provide you a short overview of a string deduplication feature added into Java 8 update 20. String objects consume a large amount of memory in an average...
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Introduction to JMH
by Mikhail Vorontsov 11 Sep 2014: Article was updated for JMH 1.0. 10 May 2014: Original version. Introduction This article will give you an overview of basic rules and abilities of JMH. The second...
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Large HashMap overview: JDK, FastUtil, Goldman Sachs, HPPC, Koloboke, Trove
by Mikhail Vorontsov This article is outdated! A newer version covering the latest versions of collections libraries is available here. 04 Jan 2015 update: a couple of clarifications, fixed a bug in...
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Performance of various general compression algorithms – some of them are...
by Mikhail Vorontsov 07 Jan 2015 update: extending LZ4 description (thanks to Mikael Grev for a hint!) This article will give you an overview of several general compression algorithm implementations...
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Going over Xmx32G heap boundary means you will have less memory available
by Mikhail Vorontsov This small article will remind you what happens to Oracle JVM once your heap setting goes over 32G. By default, all references in JVM occupy 4 bytes on heaps under 32G. This...
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Large HashMap overview: JDK, FastUtil, Goldman Sachs, HPPC, Koloboke, Trove –...
by Mikhail Vorontsov This is a major update of the previous version of this article. The reasons for this update are: The major performance updates in fastutil 6.6.0 Updates in the “get” test from the...
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Implementing a world fastest Java int-to-int hash map*
by Mikhail Vorontsov * Fastest among int-to-int map implementations I have tested in my previous article in the tests I have implemented for that article. I would like to thank Sebastiano Vigna and...
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Oracle Java Mission Control Overview
by Mikhail Vorontsov Introduction This article will describe the Java Mission Control – a JDK GUI tool (jmc / jmc.exe) available since Java 7u40. We will also discuss Java Flight Recorder – a...
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String switch implementation
by Mikhail Vorontsov This article covers the implementation details of String switch introduced in Java 7. It is a syntactic sugar on top of the normal switch operator. Suppose you have the following...
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Java server application troubleshooting using JDK tools
by Mikhail Vorontsov 1. Introduction 2. Troubleshooting scenarios 2.1. Getting a list of running JVMs 2.2. Making a heap dump 2.3. Analyzing a class histogram 2.4. Making a thread dump...
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