Tuesday, April 7, 2009

Maven : Java Profiling

At workplace I use maven extensively. In fact I like maven so much that I am slowly moving lot of java eclipse project into maven project. Maven has very good eclipse plugin which makes integration with Eclipse very easy. You can run maven from eclipse. Maven is really good tool. If you have any specific needs you can write your own plugin. At my previous workplace, senior engineer in my project automated everything (starting jboss servers on remote machine in various environments : testing, perf-testing, integration testing etc. database population, database schema drop/rebuild etc).

But now I wanted to profile java application which I used to run from maven. One of the best part of maven is dependency management and repository - it builds classpath automatically for you, but then its pain too. If you want to run java application you have to do through Maven. There is exec plugin with which you can run any Application or shell script and there is exec:java with which you can run java Main class. The problem is that exec:java is in same JVM. So you cant run any java agent(-agent) or other things : Specifically Java Profiling. You should make sure you run the application within the same environment/settings.

So my first task was to get the complete classpath and then launch java with profiler java options. I am using jprofiler which uses JVMTI agent hence you need to append "-agentlib:jprofilerti=port=31757 -Xbootclasspath/a:/Applications/jprofiler5/bin/agent.jar" to java command line.

Here is little shell script through which I managed to do java profiling for maven Project. This will work only for J2SE applications tough!. Frustrating part was variable DYLD_LIBRARY_PATH. I was new to MacOS and was trying with usual LD_LIBRARY_PATH and -agentpath jvm option. Surprisingly -agentpath option should work on MacOS but it didnt work i guess some problem with Jprofiler binary. But lastly i managed to profile my application properly.

mvn dependency:build-classpath -Dmdep.outputFile=mycp.txt
export CLASSP=`cat ./mycp.txt`
export DYLD_LIBRARY_PATH=$DYLD_LIBRARY_PATH:/Applications/jprofiler5/bin/macos
$JAVA_HOME/bin/java -cp $CLASSP:./target/classes -agentlib:jprofilerti=port=31757 -Xbootclasspath/a:/Applications/jprofiler5/bin/agent.jar $*

This is the first time I had to do away with maven command. I wished somebody had written maven plugin for lauching jprofiler enabled apps. There is maven plugin for Yourkit Java Profiler : http://code.google.com/p/maven-yourkit-plugin/ but it did now work.

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