I'm trying to collect software code metrics in my Java project on every cycle of continuous integration. I'm interested mostly in size-related metrics like number of classes, number of methods, function points, lines of code, etc. I would like to get a summary report with these metrics in some XML file. Later I will use it in project report, or somehow else.
Is there any free open-source tool which I can integrate with Maven for this purpose?
Take a look at the javancss-maven-plugin.
JavaNCSS is a source measurement suite for Java which produces quantity & complexity metrics for your java source code.
This plugin provides the capability to run the JavaNCSS tool on your Maven 2 project sources and produce an html report. Optionally you can fail the build whenever one of the metrics goes beyond a fixed limit.
One good option is Sonar.
Its primary purpose is to manage technical debt, so it does a lot of things you don't need, but it provides really good metrics.
You can integrate it with Hudson or whatever other continuous integration system you are using.
I'll throw in XRadar which provides similar functionality to Sonar.