public class NetText extends BusinessEntity<Long> implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "MySeq")
    @SequenceGenerator(name = "MySeq", sequenceName = "SEQ_NTSTATE_ID")
    @Column(name = "nettext_state_id", updatable = false, nullable = false)
    private Long id;

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "netText")
    @Cascade({ CascadeType.SAVE_UPDATE })
    private Set<NetTextStage> stages = new HashSet<NetTextStage>();

    public void addNetTextStage(NetTextStage netTextStage) {
        netTextStage.setNetText(this);
        stages.add(netTextStage);
    }

}

public class NetTextStage extends BusinessEntity<Long> implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "MySeq")
    @SequenceGenerator(name = "MySeq", sequenceName = "SEQ_NTSSTAT_ID")
    @Column(name = "NETTEXT_STAGE_STATE_ID", updatable = false, nullable = false)
    private Long id;

    @ManyToOne(fetch = FetchType.LAZY)
    @Cascade({ CascadeType.SAVE_UPDATE })
    @JoinColumn(name = "nettext_state_id", referencedColumnName = "nettext_state_id")
    private NetText netText;

                netText = new NetText();
        netText.setPublished(true);
        netText.addNetTextStage(netTextStage1);
        myDAO.saveOrUpdate(netText)

org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update
   at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:94)
   at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
   at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:275)
   at org.hibernate.jdbc.AbstractBatcher.prepareStatement(AbstractBatcher.java:114)
   at org.hibernate.jdbc.AbstractBatcher.prepareStatement(AbstractBatcher.java:109)
   at org.hibernate.jdbc.AbstractBatcher.prepareBatchStatement(AbstractBatcher.java:244)
   at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2242)
   at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2678)
   at org.hibernate.action.EntityInsertAction.execute(EntityInsertAction.java:79)
   at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279)
   at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:263)
   at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:167)
   at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
   at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50)
   at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1028)
   at com.hmh.platform.bts.data.access.dao.impl.nettext.NetTextDAOImplTest.setUp(NetTextDAOImplTest.java:91)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:597)
   at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
   at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
   at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
   at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:27)
   at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
   at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:82)
   at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
   at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:240)
   at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
   at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
   at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
   at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
   at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
   at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
   at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
   at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
   at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
   at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:180)
   at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46)
   at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
   at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
   at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
   at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
   at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: java.sql.BatchUpdateException: ORA-01400: cannot insert NULL into ("TXLA"."NETTEXT_STAGE_STATES"."NETTEXT_STATE_ID")

   at oracle.jdbc.driver.DatabaseError.throwBatchUpdateException(DatabaseError.java:343)
   at oracle.jdbc.driver.OraclePreparedStatement.executeBatch(OraclePreparedStatement.java:10656)
   at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:70)
   at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:268)
   ... 41 more