About constructor


JPA Persistable Types

Explains how JPA manages types, including entity classes, embeddable classes, primitive types, wrappers, string, date, enum, collections and maps.... should have a public or protected no-arg constructor. cannot be final and cannot have final ... In most cases ObjectDB can overcome a missing no-arg constructor. Aside from these constraints an entity class is like ...


com.objectdb.o.InternalException: java.lang.ArrayIndexOutOfBoundsException: null:

The following error appears under and extended persistence context, and with creation, configuration and wiring code that is known to work perfectly with EclipseLink+Glassfish: SEVERE: Unexpected internal exception ... ) { try { Constructor constructor = clazz. getConstructor ( Element . class , ...



The Query interface allows applications to obtain persistent instances, values, and aggregate data from the data store.(Interface of JDO)



An instance of this class is thrown when attempting to create an object id when the object id constructor parameter is null.(Exception of JDO)



Release date: 2011-08-10 Download (5.15 MB) Binary:  objectdb-2.2.9.zip You should start by following a  tutorial or reading the manual ...


Retrieving JPA Entity Objects

Explains how to use JPA to retrieve entity objects from the database.... of a new managed object during retrieval uses the no-arg constructor. Therefore, it is recommended to avoid unnecessary time consuming ...



Release date: 2011-09-21 Download (5.32 MB) Binary:  objectdb-2.3.0.zip You should start by following a  tutorial or reading the manual ...



This class is the abstract base class for all single field identity classes.(Class of JDO)


Visibility of changes in Transaction is not visible to a JPA QL Query

I have two simple Entities ( see attachment ) and a simple SLSB with container managed transactions which is called by a trivial servlet. Inside a UserTransaction I add a number of items then check to see that they have been added ... Integer property ;     // Bonus empty constructor generated for JPA protected Item ( ) { ... emInj ;   /** * Default constructor. */ public SLSBObjDb ( ) { ...


Multi-thread access to single EM's entities

If my entity classes have synchronized getters and setters, is it reliable for multiple threads to access a single EM's managed entities, as long as only the thread that created the EM interacts directly with it?  I've tested this and it seems to work... but I know better than to depend on the observable behavior of multithreaded code. When I run this example and examine the database, the entity contains the value set by the second thread, as expected.   ... replace every access of a persistent field (outside the constructor) with invocation of a method that ObjectDB adds to the classes ...