Tuesday Sep 16, 2008

Utilizing 64bit JVMs in Java CAPS Integration Server

A very common error that is observed with Java CAPS Integration
Server is "Out of Memory". What can we do about it?

[Read More]

Common Reasons for Out Of Memory Errors

Out Of Memory error can happen due to following reasons:



  • Garbage Collection Issues

  • Orphaned Class loaders

    • Thread context classloader

    • new Thread()

    • Dangling thread



  • Classes with following references

    • static variables

    • SQL Driver

    • Commons logging

    • java.util.logging.Level

    • Bean util

      • Details






etc..


We can analyze the problem(s) associated with such errors at application level by having GC details and/or heap dump



  • -verbose:gc with -XX:+PrintGCDetails for observing GC model for tuning or altering suitable GC for the application

  • -XX:+HeapDumpOnOutOfMemoryError

  • -Xrunhprof:heap=dump,format=b

  • jmap -dump:format=b,file=heap.bin <pid>


Analyze heap dump using Jhat



  • jhat -J-mx1024m heap.bin

  • http://localhost:7000

  • Using built-in or custom queries to narrow down leak suspects

  • Identify an object or class in the application

  • List reference chains

Wednesday Apr 04, 2007

Using Scripting Service in open-esb

1st part of the writeup on Scripting Service Engine. This note delves on how is scripting important for Java platform, what is JSR223 and a bit of internals on the same as a precursor to the usage of Scripting Service Engine in open-esb.[Read More]
About

I was part of Sun R&D in Java CAPS and later Glassfish ESB. I moved from R&D to Consulting. I am currently working as a Solution Architect in Oracle Consulting Services (India). I was sharing my experience w.r.t. Java CAPS and other technologies during Sun period. Now in Oracle world I share my experiences with Oracle FMW product line as well as other Oracle Technologies and products.

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