java.lang.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 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 OutOfMemoryError you are dealing with, please consult the related posts...

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How to analyze Thread Dump – part 1

This article is part #1 of a series of posts that will teach you how to analyze a JVM Thread Dump and pinpoint the root cause of your problem(s). From my perspective, Thread Dump analysis is the most important skillset to master for any individual involved in Java EE production support. The amount of information that you can derive from Thread Dump snapshots is often much beyond than what you can think of. My goal is to share with you my knowledge on Thread Dump analysis that I accumulated over the last 10 years e.g. hundreds of Thread Dump analysis cycles with dozens of common problem patterns across many JVM versions and JVM vendors. Please...

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java.lang.OutOfMemoryError – Weblogic Session size too big

A major problem was brought to our attention recently following a migration of a Java EE Portal application from Weblogic 8.1 to Weblogic 11g. This case study will demonstrate how you can analyze an IBM JRE Heap Dump (.phd format) in order to determine the memory footprint of your application HttpSession objects. Environment specifications (case study) -         Java EE server: Oracle Weblogic Server...

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HashMap Thread safe problem – Case Study

This article will provide you with complete root cause analysis and solution of a java.util.HashMap Thread race condition affecting a Weblogic 10 Portal application. This case study will also demonstrate how you can combine Solaris PRSTAT and Thread Dump analysis to pinpoint you top CPU contributor Threads within your Java VM(s). Environment specifications -         Java EE server: Oracle Weblogic Portal 10 -         Middleware OS: Solaris 10 -         Java VM: Oracle Jrockit 1.5.0 -        ...

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Memory Analyzer download

Memory Analyzer (MAT) is an extremely useful tool that analyzes Java Heap Dump files with hundreds of millions of objects, quickly calculate the retained sizes of objects, see who is preventing the Garbage Collector from collecting objects, run a report to automatically extract leak suspects. Why do I need it? OutOfMemoryError problems are quite complex and require proper analysis. The tool is a must for any Java EE production support person or developer who requires to investigate memory leak and / or to analyze their application memory footprint. Where can I find tutorials and case studies? You will find from this Blog several...

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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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