Program: 90015
Project: 90015
Buggy source:
/** 
 * Ensure that a file containing the appropriate content exists for the ID. If the content cannot be found, this method may return null (if I is a simple type) or an appropriate subset (if I is, say, a Set) indicating the data that is actually available.  In the latter case, calling cache on the returned set should always fill the file for that subset (barring catastrophic failure). Locking:  If the file is not immediately found, we enter a file-creation state.  To avoid corrupted data, we must ensure that only one cache instance, and only one thread within any instance, creates the file. Thus as long as somebody else seems to be creating the file, we wait and see if they finish.  This is checked by having an exclusive lock on a ".working" file (we cannot use the result file, as it has to be created to be locked, and we may end up with a different cached file than we thought, see above).  The .working file itself is irrelevant, only the lock on it matters.
 * @param id Some sort of id that uniquely identifies the item withinthe cache.
 * @return The id given if it was successfully fetched, otherwise nullif the type parameter I does not allow subsets, or a subset of id if it does.  This subset should be immediately cacheable. FIXME added method synchronization. Try to fix bug 1547
 */
public I cache(I id){
  ArgumentNotValid.checkNotNull(id,"String_Node_Str");
  File cachedFile=getCacheFile(id);
  if (cachedFile.exists()) {
    return id;
  }
 else {
    try {
      File fileBehindLockFile=new File(cachedFile.getAbsolutePath() + "String_Node_Str");
      FileOutputStream lockFile=new FileOutputStream(fileBehindLockFile);
      FileLock lock=null;
      try {
synchronized (fileBehindLockFile.getAbsolutePath().intern()) {
          log.debug("String_Node_Str" + fileBehindLockFile.getAbsolutePath() + "String_Node_Str"+ Thread.currentThread().getName()+ "String_Node_Str");
          try {
            lock=lockFile.getChannel().lock();
          }
 catch (          OverlappingFileLockException e) {
            log.warn(e);
            throw new IOException(e);
          }
          if (cachedFile.exists()) {
            return id;
          }
          I found=cacheData(id);
          log.info("String_Node_Str" + id + "String_Node_Str"+ found);
          return id;
        }
      }
  finally {
        if (lock != null) {
          log.debug("String_Node_Str" + lockFile.getChannel());
          lock.release();
        }
        lockFile.close();
      }
    }
 catch (    IOException e) {
      String errMsg="String_Node_Str" + cachedFile.getAbsolutePath() + "String_Node_Str";
      log.warn(errMsg,e);
      throw new IOFailure(errMsg,e);
    }
  }
}

Fixed version (ground truth):
/** 
 * Ensure that a file containing the appropriate content exists for the ID. If the content cannot be found, this method may return null (if I is a simple type) or an appropriate subset (if I is, say, a Set) indicating the data that is actually available.  In the latter case, calling cache on the returned set should always fill the file for that subset (barring catastrophic failure). Locking:  If the file is not immediately found, we enter a file-creation state.  To avoid corrupted data, we must ensure that only one cache instance, and only one thread within any instance, creates the file. Thus as long as somebody else seems to be creating the file, we wait and see if they finish.  This is checked by having an exclusive lock on a ".working" file (we cannot use the result file, as it has to be created to be locked, and we may end up with a different cached file than we thought, see above).  The .working file itself is irrelevant, only the lock on it matters.
 * @param id Some sort of id that uniquely identifies the item withinthe cache.
 * @return The id given if it was successfully fetched, otherwise nullif the type parameter I does not allow subsets, or a subset of id if it does.  This subset should be immediately cacheable. FIXME added method synchronization. Try to fix bug 1547
 */
public I cache(I id){
  ArgumentNotValid.checkNotNull(id,"String_Node_Str");
  File cachedFile=getCacheFile(id);
  if (cachedFile.exists()) {
    return id;
  }
 else {
    try {
      File fileBehindLockFile=new File(cachedFile.getAbsolutePath() + "String_Node_Str");
      FileOutputStream lockFile=new FileOutputStream(fileBehindLockFile);
      FileLock lock=null;
      try {
synchronized (fileBehindLockFile.getAbsolutePath().intern()) {
          log.debug("String_Node_Str" + fileBehindLockFile.getAbsolutePath() + "String_Node_Str"+ Thread.currentThread().getName()+ "String_Node_Str");
          try {
            lock=lockFile.getChannel().lock();
          }
 catch (          OverlappingFileLockException e) {
            log.warn(e);
            throw new IOException(e);
          }
          if (cachedFile.exists()) {
            return id;
          }
          return cacheData(id);
        }
      }
  finally {
        if (lock != null) {
          log.debug("String_Node_Str" + lockFile.getChannel());
          lock.release();
        }
        lockFile.close();
      }
    }
 catch (    IOException e) {
      String errMsg="String_Node_Str" + cachedFile.getAbsolutePath() + "String_Node_Str";
      log.warn(errMsg,e);
      throw new IOFailure(errMsg,e);
    }
  }
}