Program: 91500
Project: 91500
Buggy source:
/** 
 * Find directories containing .project files recursively starting at given directory
 * @param files
 * @param directory
 * @param visistedDirs
 * @param monitor
 * @return true if projects files found, false otherwise
 */
public static boolean findProjectFiles(final Collection<File> files,final File directory,final Set<String> visistedDirs,final IProgressMonitor monitor){
  IProgressMonitor pm=monitor;
  if (pm == null)   pm=new NullProgressMonitor();
 else   if (pm.isCanceled())   return false;
  monitor.subTask(NLS.bind(CoreText.ProjectUtil_taskCheckingDirectory,directory.getPath()));
  final File[] contents=directory.listFiles();
  if (contents == null || contents.length == 0)   return false;
  Set<String> directoriesVisited;
  if (visistedDirs == null) {
    directoriesVisited=new HashSet<String>();
    try {
      directoriesVisited.add(directory.getCanonicalPath());
    }
 catch (    IOException exception) {
      Activator.logError(exception.getLocalizedMessage(),exception);
    }
  }
 else   directoriesVisited=visistedDirs;
  final String dotProject=IProjectDescription.DESCRIPTION_FILE_NAME;
  for (int i=0; i < contents.length; i++) {
    File file=contents[i];
    if (file.isFile() && file.getName().equals(dotProject)) {
      files.add(file);
      return true;
    }
  }
  for (int i=0; i < contents.length; i++) {
    if (!contents[i].isDirectory())     continue;
    if (contents[i].getName().equals(METADATA_FOLDER))     continue;
    try {
      String canonicalPath=contents[i].getCanonicalPath();
      if (!directoriesVisited.add(canonicalPath)) {
        continue;
      }
    }
 catch (    IOException exception) {
      Activator.logError(exception.getLocalizedMessage(),exception);
    }
    findProjectFiles(files,contents[i],directoriesVisited,pm);
  }
  return true;
}

Fixed version (ground truth):
/** 
 * Find directories containing .project files recursively starting at given directory
 * @param files
 * @param directory
 * @param visistedDirs
 * @param monitor
 * @return true if projects files found, false otherwise
 */
public static boolean findProjectFiles(final Collection<File> files,final File directory,final Set<String> visistedDirs,final IProgressMonitor monitor){
  if (directory == null)   return false;
  IProgressMonitor pm=monitor;
  if (pm == null)   pm=new NullProgressMonitor();
 else   if (pm.isCanceled())   return false;
  monitor.subTask(NLS.bind(CoreText.ProjectUtil_taskCheckingDirectory,directory.getPath()));
  final File[] contents=directory.listFiles();
  if (contents == null || contents.length == 0)   return false;
  Set<String> directoriesVisited;
  if (visistedDirs == null) {
    directoriesVisited=new HashSet<String>();
    try {
      directoriesVisited.add(directory.getCanonicalPath());
    }
 catch (    IOException exception) {
      Activator.logError(exception.getLocalizedMessage(),exception);
    }
  }
 else   directoriesVisited=visistedDirs;
  final String dotProject=IProjectDescription.DESCRIPTION_FILE_NAME;
  for (int i=0; i < contents.length; i++) {
    File file=contents[i];
    if (file.isFile() && file.getName().equals(dotProject)) {
      files.add(file);
      return true;
    }
  }
  for (int i=0; i < contents.length; i++) {
    if (!contents[i].isDirectory())     continue;
    if (contents[i].getName().equals(METADATA_FOLDER))     continue;
    try {
      String canonicalPath=contents[i].getCanonicalPath();
      if (!directoriesVisited.add(canonicalPath)) {
        continue;
      }
    }
 catch (    IOException exception) {
      Activator.logError(exception.getLocalizedMessage(),exception);
    }
    findProjectFiles(files,contents[i],directoriesVisited,pm);
  }
  return true;
}