persistence

I have problem with getting rows from my database using Hibernate. When I would like to get only one row, I am receiving 20. When I would like to get all of rows from table with about 1.5k rows, I am receiving exactly 15.2k rows. Entity class of this table has composite primary key. This is my code for getting all rows: Criteria criteria = getSession().createCriteria(type); criteria.setCacheable(true).setCacheRegion(BaseEntity.PACKAGE); criteria.list(); And this is my Entity class: @javax.persistence.Entity @Table(name = "my_table") public class My extends MyEntity<MyPK> { @EmbeddedId private

I'm having some trouble using Persistence on my jBPM project. My configuration is jBPM 5.4 + Hibernate + JPA 2, and I'm currently setting up the process flow to connect to a DB with persistence, through persistence.xml. I'm just trying to connect the default data source (in the H2 server) with my custom persistence.xml, but I keep getting the same error over and over again: Unknown entity: org.jbpm.persistence.processinstance.ProcessInstanceInfo I've manually added to my src/META-INF folder the JBPMorm-JPA2.xml the following content, but the error still persists. Can anyone help me? JBPMorm

I am developing a stand-alone java application which uses eclipselink. It is all fine when I execute the app from eclipse IDE. But I've exported an executable JAR file, and since than I can not make eclipseLink work. I have found similar issue in the Eclipse community forum here , but yet not too handy: Please help, My exception is the following: 01 dec. 2010 22:47:31,199 INFO Configuration:97 - Iniciate database Exception in thread "main" java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke

I'm very new to Java but I've been developing a habit to use final wherever possible declaring immutability which i think is a good thing. (Consider f#) I've read that JPA does not support final fields. Hibernate, TopLink? I'm not sure about these but i prefer JPA for now. Is that even possible theoretically - let's say through reflection - to modify final fields after creation? My guess would be... NO :) What would be certainly possible for a persistence solution is to support constructors with parameters. At least i see no reason that would make this impossible. Mapping would be a little

I have a class which models all categories and they can be ordered hierarchically. @Entity @Table(name="categories") public class Category { @Id @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="sequence") @SequenceGenerator(name="sequence", sequenceName="categories_pk_seq", allocationSize=1) @Column(name="id") private Long id; @Column private String name; @OneToOne @JoinColumn(name="idfather") private Category father; } I need to get all categories ordered hierarchically (I mean every father followed by its children and fathers ordered alphabetically on each level) as they could be

In other words, can we model many to many relationships in a persistent data structure efficiently? A pair of unidirectional multimaps was suggested. However, I'm not sure how this would work well for removal in a persistent data structure. Let's take the case where we have keys 1..4 to values "1".."4" and let's say they each refer to all the others, so we have two maps that look very similar for both directions: {1 => ["2","3","4"], 2 => ["1","3","4"], ...} {"1" => [2,3,4], "2" => [1,3,4], ...} Now we want to remove item 1 completely from the system. That requires changing one node in the