Re: Executing multiple methods on same java instance

=?ISO-8859-1?Q?Arne_Vajh=F8j?= <>
Sat, 05 May 2007 20:14:50 -0400
<463d1df2$0$90269$> wrote:

I hope the following code snippet could explain my scenario better. I
have a Object locator method which based on config properties, does a
EJB look up for home object or a POJO instantiation and provides the
Object back.

While doing so, it also places the object reference in a HashMap for
future use.
Now I am not sure if this would be tread safe with the entire class
being a singleton class.

if (businessServices.get(taskId) != null) {
    obj = businessServices.get(taskId);
             /String serviceType =

    //if the business service is of JNDI type , it will proceed in the
else part
         if((serviceType != null) &&
                Context initialContext = new InitialContext(env);
                obj = initialContext.lookup(jndiName);
    Class clazz = Class.forName(homeClass) ;
    Object home = (EJBHome) PortableRemoteObject.narrow(obj, clazz);
    obj = home;
    businessServices.put(taskId, obj);

         }else if ((serviceType != null) &&
    obj = Class.forName(className);
    businessServices.put(taskId, obj);
  return obj;

This code is not thread safe.

You should synchronize on businessServices where you
update it.

You do not need to worry about the test if it is already
in the hash table. A race condition could cause two
threads to both initialize, but it does not matter.


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