About Time


Working with a cleared cache

I'm working on trying to improve the performance of our database processing class and I'm attempting to keep the L1 cache within the PersistenceManager cleared in an effort to reduce its memory footprint. The code snippet below is part of a Callable task that is run repeatedly with a given list of commands. When I run the code as written I start getting the stack traces that are listed.  However, if I comment out the calls to makeTransactionalAll() and evictAll() everything works.... one thread will be accessing the PersistenceManager at a time. One of my next steps will be to increase the number of threads so if you ...


Download ObjectDB

Free download of the ObjectDB object database for Java with JPA and JDO support.... and one million entity objects per database file (no time limit). You need a license to remove these limits. ...


Retrieving JPA Entity Objects

Explains how to use JPA to retrieve entity objects from the database.... Therefore, it is recommended to avoid unnecessary time consuming operations in no-arg constructors of entity classes and to keep ...



This class is a helper class for JDO implementations.(Class of JDO)



Flushing to occur at transaction commit.(Enum Constant of javax.persistence.FlushModeType)


Pessimistic lock timeout - blocks indefinitely

I've attached a simple test which creates an object then kicks off several threads which each try to update the object. I'm using a pessimistic lock with timeout as follows: ... 1000ms the blocked threads get released at the correct time but thrown a LockTimeoutException implying that the first lock wasn't ...



Set the ignoreCache option.(Method of javax.jdo.Query)


Cannot initialize db after inserting a java.util.List

Hi, I've spent some time trying to figure this out without success, so I'm asking for much appreciated help. I have an entity class like this: class Test { private List<String> list = new ArrayList<String>(); } I can persist and retrieve the obj just fine using standalone program, but whenever I access the db through a servlet container I get this error: objectdb.java.util.ArrayList cannot be cast to com.objectdb.spi.TrackableSysType This happens during EntityManagerFactory initialization.... Hi, I've spent some time trying to figure this out without success, so I'm asking for much ...



Thrown by the persistence provider when EntityManager.persist(Object) is called and the entity already exists.(Exception of JPA)


Recursive calls with @PreUpdate annotation and Glassfish OutOfMemoryError

Hi,    I've had an issue that started today and it's got me stumped. I've got a subclass User, which extends a BaseEntity. The BaseEntity has a @PreUpdate as per: ... and until I remove the enhancement (I do this build time with maven). First, for the test case I supplied: 1) You ...