http://cobertura.sourceforge.net: Cobertura is a free Java tool that calculates the percentage of code accessed by tests. It can be used to identify which parts of your Java program are lacking test coverage. It is based on jcoverage.
  • Steven Christou 
package net.sourceforge.cobertura.reporting;

import net.sourceforge.cobertura.dsl.ReportFormat;

import java.util.HashSet;
import java.util.Set;

public class CompositeReport implements Report {

	private Set<Report> reports;

	public CompositeReport() {
		reports = new HashSet<Report>();
		reports.add(new NullReport());
	}

	public void export(ReportFormat reportFormat) {
		for (Report report : reports) {
			report.export(reportFormat);
		}
	}

	public ReportName getName() {
		return ReportName.COMPOSITE_REPORT;
	}

	public Report getByName(ReportName name) {
		if (ReportName.COMPOSITE_REPORT.equals(name)) {
			return this;
		}
		for (Report report : reports) {
			if (report.getName().equals(name)) {
				return report;
			}
		}
		return getByName(ReportName.NULL_REPORT);
	}

	public void addReport(Report report) {
		reports.add(report);
	}
}