Serialization infinite data

Have you ever seen this serializing java data? The writer gets stuck and writes forever until the filesystem fulls up. I had fairly simple object to serialize, just

HashMap<String,<HashMap<String, Double>>

And there was no chance that one hashmap contained the other. Any ideas?

	OutputStream fos=null, bos=null, ooos=null;
	try {
	  fos = new FileOutputStream(f);
	  bos = new BufferedOutputStream(fos,4096);
	  ObjectOutputStream oos = new ObjectOutputStream(bos);
	  ooos = oos;
	  oos.writeObject(sr);
	} catch (IOException e){
		throw e; 
	}  finally {
	  if (ooos!=null) ooos.close();
	  if (bos!=null) bos.close();
	  if (fos!=null) fos.close();