CODEWITHSUNDEEP
javaserializationjsf-2
Flyhard
Flyhard

Reputation: 554

Tracking down serialization issues in JSF application

We have a JSF application that gives us NotSerializableException sometimes without us knowing which object presents the problem. The Stacktrace gives little clue since it states that "Object" is the type that cannot be serialized.

I'd like to find the different approaches to locating the field.

We have solved the issue with the solution I posted, but I'd like to a) share it and b) see if this can be improved upon.

Upvotes: 2

Views: 173

Answers (1)

Flyhard
Flyhard

Reputation: 554

We created the following class and adding it as a listener to web.xml. This incurres a performance hit, so don't forget to remove it again if performance is an issue. This caught most of our serialization issues except for serialization of a servlet on the cluster.

public class SessionAttributeTracker implements HttpSessionAttributeListener
{

  private static final Logger logger = LoggerFactory.getLogger(SessionAttributeTracker.class);

  @Override
  public void attributeAdded(final HttpSessionBindingEvent sessionBindingEvent)
  {
    Object obj = sessionBindingEvent.getValue();
    logger.debug("Session attribute added: {}", obj);
    if (!isSerializable(obj))
    {
      logger.warn("Attribute '{}' added to session with non-serializable object: {}",
          sessionBindingEvent.getName(),
          sessionBindingEvent.getValue());

    }
  }

  private boolean isSerializable(final Object obj)
  {
    logger.debug("Checking serializability of : {}", obj.getClass().getName());
    boolean ret = false;
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    ObjectOutputStream oos = null;
    try
    {
      oos = new ObjectOutputStream(out);
      oos.writeObject(obj);
      ret = true;
    }
    catch (Exception e)
    {
      for (Field f : obj.getClass().getDeclaredFields())
      {
        logger.trace("obj {} felt {}", obj, f.getName());
        if ((f.getModifiers() & Modifier.TRANSIENT) == 0)
        {
          f.setAccessible(true);
          try
          {
            Object object = f.get(obj);
            oos = new ObjectOutputStream(out);
//          logger.debug("Hopper over writeObject");
            oos.writeObject(object);
          }
          catch (Exception e1)
          {
            logger.debug("Problem encountered while serializing attribute {}", f.getName(), e1);
          }
        }
      }
      logger.warn("Serilization problem.", e);
      return ret;
    }
    finally
    {
      IOUtils.closeQuietly(oos);
    }
    return ret;
  }

  private String threadDump()
  {
    StringBuffer fullThreadDump = new StringBuffer();
    Thread t = Thread.currentThread();
    State state = t.getState();
    String tName = t.getName();
    if (state != null)
    {
      fullThreadDump.append("   ").append(tName).append(": ").append(state).append("\n");
    }
    StackTraceElement[] stes = t.getStackTrace();
    for (StackTraceElement stackTraceElement : stes)
    {
      fullThreadDump.append("     at ").append(stackTraceElement).append("\n");
    }

    return fullThreadDump.toString();
  }

  @Override
  public void attributeRemoved(final HttpSessionBindingEvent sessionBindingEvent)
  {
  }

  @Override
  public void attributeReplaced(final HttpSessionBindingEvent sessionBindingEvent)
  {
  }

}

Upvotes: 2

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