code: @SuppressWarnings("PMD.AvoidThreadGroup")
      private String[] findFiles(final File workspaceRoot) {
          FileSet fileSet = new FileSet();
          org.apache.tools.ant.Project project = new org.apache.tools.ant.Project();
          fileSet.setProject(project);
          fileSet.setDir(workspaceRoot);
          fileSet.setIncludes(filePattern);
  
          if (StringUtils.isNotBlank(excludeFilePattern)) {
              fileSet.setExcludes(excludeFilePattern);
          }
  
          log("Scanning folder '" + workspaceRoot + "' for files matching the pattern '" + filePattern
                  + "' - excludes: " + excludeFilePattern);
  
          return fileSet.getDirectoryScanner(project).getIncludedFiles();
      }
docs: Returns an array with the filenames of the files that have been found in
  the workspace.
  
  @param workspaceRoot
  root directory of the workspace
  @return the filenames of the FindBugs files