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JRockit – JRCMD useful commands

I have been using JRockit since many years 2007. I find it slower than Hotspot, but it has been always better on diagnosis and analysis of problems. Since last summer, I have been working for an international telecommunication systems vendor. We design and implement various products for telecom operators, on top of HP OpenCall Convergent Communication Platform. I am fan ...

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Tracking excessive garbage collection in Hotspot JVM

Quite frequently due to memory leaks or other memory problems applications freeze leaving only the garbage collector (GC) process running unsuccessfully trying to free some space. This happens until watchdog (or frustrated administrator) restarts the application and the problem is never solved. The goal of this article is to show how to identify excessive GC and to get a heap ...

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Just in Time Compiler (JIT) in Hotspot

The Just In Time Compiler (JIT) concept and more generally adaptive optimization is well known concept in many languages besides Java (.Net, Lua, JRuby). In order to explain what is JIT Compiler I want to start with a definition of compiler concept. According to wikipedia compiler is ‘ a computer program that transforms the source language into another computer language ...

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How to analyze Thread Dump – IBM VM

This article is part 4 of our Thread Dump analysis series which will provide you with an overview of what is a JVM Thread Dump for the IBM VM and the different Threads and data points that you will find. As you will see and learn, the IBM VM Thread Dump format is different but provides even more out-of-the-box troubleshooting ...

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OutOfMemoryError: Java heap space – Analysis and resolution approach

 java.lang.OutOfMemoryError: Java heap problem is one of the most complex problems you can face when supporting or developing complex Java EE applications. This short article will provide you with a description of this JVM HotSpot OutOfMemoryError error message and how you should attack this problem until its resolution. For a quick help guide on how to determine which type of ...

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GC overhead limit exceeded – Java Heap analysis

This post is the continuation of our original GC overhead limit exceeded problem patterns post. Proper Java Heap analysis is critical in order to eliminate your OutOfMemoryError: GC overhead problem. If you are not familiar with this Java HotSpot 1.6 error, I recommend that you first review my First Article on this subject. This article will provide you with a ...

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Java High CPU troubleshooting guide – part 1

This article is part 1 of a series that will provide you with a comprehensive guide on how you can troubleshoot and identify root cause of Java high CPU problems. This guide is also applicable for standalone Java programs but designed to help individuals involved in day to day Java EE enterprise production support. It will also include the list ...

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HPROF – Memory leak analysis tutorial

This article will provide you with a tutorial on how you can analyze a JVM memory leak problem by generating and analyzing a Sun HotSpot JVM HPROF Heap Dump file. A real life case study will be used for that purpose: Weblogic 9.2 memory leak affecting the Weblogic Admin server. Environment specifications Java EE server: Oracle Weblogic Server 9.2 MP1 ...

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Java Thread CPU analysis on Windows

This article will provide you with a tutorial on how you can quickly pinpoint the Java Thread contributors to a high CPU problem on the Windows OS. Windows, like other OS such as Linux, Solaris & AIX allow you to monitor the CPU utilization at the process level but also for individual Thread executing a task within a process. For ...

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