Better jcov integration

[Alexey Fedorchenko]

Hello, Eric!

Thank you for the report. I have added an issue for your request [1].
We will address it, I also think that having more report formats is a good suggestion.

A few thoughts about the original problem of adding JCov to CI (Jenkins):
- use html publisher plugin to show JCov html report
- plot build data with plot plugin to look at the coverage trend for builds 
( it will require using grep and sed to get data from overview-summary.html to plot.csv )
- create JCov plugin for Jenkins.

The latest item and Maven plugin opens a little bit bigger discussion for Code Tools projects:
Could we have tool's plugins sources in tool’s repository?

Thank you.

[1] https://bugs.openjdk.java.net/browse/CODETOOLS-7902125 <https://bugs.openjdk.java.net/browse/CODETOOLS-7902125>

—Alexey

> On Feb 28, 2018, at 4:42 AM, Eric McCorkle <eric at metricspace.net> wrote:
> 
> Hello everyone,
> 
> I recently found myself needing better integration of jcov into various
> build/testing tools, so I did two things.  First, I modified the jcov
> tool to generate a report in the Cobertura XML format, which is used by
> Jenkins and other tools as an input format.  While these reports are
> inferior in my opinion to the HTML reports jcov generates, they do allow
> integration with other tools and CI systems.  Therefore, I think
> providing this functionality would likely encourage more people to use
> jcov over the alternatives.
> 
> I've attached the patch for this modification here, if anyone would like
> to review it.
> 
> 
> I've also mostly wrangled the Maven plugin API to create a plugin for
> using jcov in a Maven project (however, there is one remaining issue
> with documentation generation that I need to correct before I call the
> plugin "finished").  I'm not sure if that would be something that would
> be added to codetools, if the group ID should be something like
> "org.openjdk", or what else ought to be done about it.  I will gladly
> contribute the code if there's a desire to adopt it.
> <cobertura.diff>