I want to check how/if the get-method works fine, but unfortunately it doesn't. My test is this. First save an object to the database, and then check if I can retrieve it. If I can, it means the object is in the database, otherwise not. The CommsIn class implements Serializable and is the class used for the test.

Here is the code :

/**
* persist a transient object to the database
*/
public void create( Object obj ) throws PersistenceException
{
Session sess;

try
{

sess = sessionFactory.openSession();

// Save the object to the database
Transaction t = sess.beginTransaction();
sess.save( obj );
t.commit();

sess.close();

// Call isPersisten to see if it's in the database
System.out.println("isPersistent => " + isPersistent(CommsIn.class,(Serializable) obj));
}
catch ( Throwable e )
{}


/**
* check if an object is already persisted in database
*
* @param clazz a persistent class
* @param id an identifier
*
* @return true if object already persisted, false otherwise
*/
public boolean isPersistent( Class clazz, Serializable id ) throws PersistenceException
{
Object obj = null;
Session sess;

boolean isPersisted = false ;

try
{
// Check if the object is persisted
sess = sessionFactory.openSession( );
obj = sess.get(clazz, id);
sess.close();
return obj != null ? true : false;
}
catch ( Throwable e )
{
LogUtils.logProblem( logger,"cannot check if object of type " + obj.getClass( ).getName( ) + " is persistent " +" " + e.getMessage);

But I get this Exception :

com.hp.mw.csf.AccessManager - cannot create object of type com.abpro.babel.CommsIn null
java.lang.NullPointerException

when running the line :
obj = sess.get(clazz, id);

in the isPersistent method.
Ideas ?

Passing in obj as your Serializable id may have something to do with it :)


System.out.println("isPersistent => " + isPersistent(CommsIn.class,(Serializable) obj));

You are right, now it works :=)

The change to do is to write :

sess.get(CommsIn.class, sess.getIdentifier(obj)

Thanks a lot !