Java Code Geeks » Pierre Hugues Charbonneau http://www.javacodegeeks.com/ Java 2 Java Developers Resource Center Fri, 22 May 2015 19:00:21 +0000 en-US hourly 1 http://wordpress.org/?v=4.2.2 ClassNotFoundException: is it slowing down your JVM?http://www.javacodegeeks.com/2014/04/classnotfoundexception-is-it-slowing-down-your-jvm.html http://www.javacodegeeks.com/2014/04/classnotfoundexception-is-it-slowing-down-your-jvm.html#comments Thu, 10 Apr 2014 07:00:36 +0000 http://www.javacodegeeks.com/?p=22858 Most Java developers are familiar with the infamous and very common java.lang.ClassNotFoundException. While the sources of this problem are generally well understood (missing classes/libraries in classpath, class loader delegation problems etc.), the impact to the overall JVM and performance is often unknown. This situation can lead to significant impacts to your application response time and ...

 

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Java VM – Beware of the YoungGen spacehttp://www.javacodegeeks.com/2013/11/java-vm-beware-of-the-younggen-space.html http://www.javacodegeeks.com/2013/11/java-vm-beware-of-the-younggen-space.html#comments Tue, 19 Nov 2013 08:00:53 +0000 http://www.javacodegeeks.com/?p=18971 As you may have seen from our previous performance oriented articles, a healthy JVM is one of the most important goals to achieve for optimal application performance and stability. Such health assessment is very often only focusing on the frequency (avoidance) of major collections or detecting the presence of memory leaks. What about the sizing ...

 

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Java Just-In-Time compilation: more than just a buzzwordhttp://www.javacodegeeks.com/2013/07/java-just-in-time-compilation-more-than-just-a-buzzword.html http://www.javacodegeeks.com/2013/07/java-just-in-time-compilation-more-than-just-a-buzzword.html#comments Fri, 12 Jul 2013 07:00:47 +0000 http://www.javacodegeeks.com/?p=15395 A recent Java production performance problem forced me to revisit and truly appreciate the Java VM Just-In-Time (JIT) compiler. Most Java developers and support individuals have heard of this JVM run time performance optimization but how many truly understand and appreciate its benefits? This article will share with you a troubleshooting exercise I was involved ...

 

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GC Memory Visualizer Tutorial – Part1http://www.javacodegeeks.com/2013/06/gc-memory-visualizer-tutorial-part1.html http://www.javacodegeeks.com/2013/06/gc-memory-visualizer-tutorial-part1.html#comments Sat, 15 Jun 2013 12:00:15 +0000 http://www.javacodegeeks.com/?p=14241 As you may have read from past articles, one of the key Java programmer skills to acquire is your ability to understand and assess the health of the JVM such as the Java heap memory footprint along with the garbage collection process. In order to achieve the above goals, all JVM vendors (Oracle, IBM…) provide, ...

 

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HotSpot GC Thread CPU footprint on Linuxhttp://www.javacodegeeks.com/2013/04/hotspot-gc-thread-cpu-footprint-on-linux.html http://www.javacodegeeks.com/2013/04/hotspot-gc-thread-cpu-footprint-on-linux.html#comments Mon, 22 Apr 2013 19:00:52 +0000 http://www.javacodegeeks.com/?p=11588 The following question will test your knowledge on garbage collection and high CPU troubleshooting for Java applications running on Linux OS. This troubleshooting technique is especially crucial when investigating excessive GC and / or CPU utilization. It will assume that you do not have access to advanced monitoring tools such as Compuware dynaTrace or even ...

 

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OpenJPA: Memory Leak Case Studyhttp://www.javacodegeeks.com/2013/03/openjpa-memory-leak-case-study.html http://www.javacodegeeks.com/2013/03/openjpa-memory-leak-case-study.html#comments Fri, 15 Mar 2013 08:00:00 +0000 http://www.javacodegeeks.com/?p=9880 This article will provide the complete root cause analysis details and resolution of a Java heap memory leak (Apache OpenJPA leak) affecting an Oracle Weblogic server 10.0 production environment. This post will also demonstrate the importance to follow the Java Persistence API best practices when managing the javax.persistence.EntityManagerFactory lifecycle.             ...

 

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Java concurrency: the hidden thread deadlockshttp://www.javacodegeeks.com/2013/02/java-concurrency-the-hidden-thread-deadlocks.html http://www.javacodegeeks.com/2013/02/java-concurrency-the-hidden-thread-deadlocks.html#comments Fri, 08 Feb 2013 14:00:33 +0000 http://www.javacodegeeks.com/?p=8302 Most Java programmers are familiar with the Java thread deadlock concept. It essentially involves 2 threads waiting forever for each other. This condition is often the result of flat (synchronized) or ReentrantLock (read or write) lock-ordering problems.                 Found one Java-level deadlock: ============================= "pool-1-thread-2": waiting to lock monitor ...

 

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Java 8: From PermGen to Metaspacehttp://www.javacodegeeks.com/2013/02/java-8-from-permgen-to-metaspace.html http://www.javacodegeeks.com/2013/02/java-8-from-permgen-to-metaspace.html#comments Tue, 05 Feb 2013 08:00:04 +0000 http://www.javacodegeeks.com/?p=8079 As you may be aware, the JDK 8 Early Access is now available for download. This allows Java developers to experiment with some of the new language and runtime features of Java 8. One of these features is the complete removal of the Permanent Generation (PermGen) space which has been announced by Oracle since the ...

 

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QOTD: Java Thread vs. Java Heap Spacehttp://www.javacodegeeks.com/2013/01/qotd-java-thread-vs-java-heap-space.html http://www.javacodegeeks.com/2013/01/qotd-java-thread-vs-java-heap-space.html#comments Wed, 16 Jan 2013 14:00:43 +0000 http://www.javacodegeeks.com/?p=7076 The following question is quite common and is related to OutOfMemoryError: unable to create new native thread problems during the JVM thread creation process and the JVM thread capacity. This is also a typical interview question I ask to new technical candidates (senior role). I recommend that you attempt to provide your own response before ...

 

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Java Thread: retained memory analysishttp://www.javacodegeeks.com/2012/12/java-thread-retained-memory-analysis.html http://www.javacodegeeks.com/2012/12/java-thread-retained-memory-analysis.html#comments Mon, 31 Dec 2012 20:00:12 +0000 http://www.javacodegeeks.com/?p=6238 This article will provide you with a tutorial allowing you to determine how much and where Java heap space is retained from your active application Java threads. A true case study from an Oracle Weblogic 10.0 production environment will be presented in order for you to better understand the analysis process. We will also attempt ...

 

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