Error changing db from sqlserver to mysql

Question

Hi all,
I tried to switch my project from sqlserver to mysql.
I copied table structures and all the data from one db to the other.
I changed persistence xml to fill the new parameters of the db.
In my mind these should be the changes needed, and everything should work in the same way and in fact the majority part of my project works fine.
My problem is that when I execute a specific page list I got the following error :
javax.servlet.ServletException: /elaborazioni/wkfoperd/tiles/ListBody.jsp(58,8) '#{wkfoperd.wkfoperdItems}' Error reading 'wkfoperdItems' on type operazioniSospette.jsf.WkfoperdController
     javax.faces.webapp.FacesServlet.service(FacesServlet.java:256)
     org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:178)
     org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290)
     org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:390)
     org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:517)
     util.SecurityFilter.doFilter(SecurityFilter.java:52)
     org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390)
while the stack trace of the log reports the following :
Caused by: org.apache.jasper.el.JspELException: /elaborazioni/wkfoperd/tiles/ListBody.jsp(58,8) '#{wkfoperd.wkfoperdItems}' Error reading 'wkfoperdItems' on type operazioniSospette.jsf.WkfoperdController
at org.apache.jasper.el.JspValueExpression.getValue(JspValueExpression.java:107)
at javax.faces.component.UIData.getValue(UIData.java:582)
at javax.faces.component.UIData.getDataModel(UIData.java:1063)
at javax.faces.component.UIData.setRowIndex(UIData.java:417)
at com.sun.faces.renderkit.html_basic.TableRenderer.encodeBegin(TableRenderer.java:85)
at javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:788)
at javax.faces.component.UIData.encodeBegin(UIData.java:879)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java:269)
at com.sun.faces.renderkit.html_basic.GroupRenderer.encodeChildren(GroupRenderer.java:117)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:812)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:886)
at javax.faces.render.Renderer.encodeChildren(Renderer.java:137)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:812)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java:271)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java:276)
at com.sun.faces.renderkit.html_basic.GridRenderer.encodeChildren(GridRenderer.java:242)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:812)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:886)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:892)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:892)
at com.sun.faces.application.ViewHandlerImpl.doRenderView(ViewHandlerImpl.java:245)
at com.sun.faces.application.ViewHandlerImpl.renderView(ViewHandlerImpl.java:176)
at org.ajax4jsf.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:100)
at org.ajax4jsf.application.AjaxViewHandler.renderView(AjaxViewHandler.java:176)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:106)
at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:251)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:144)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:245)
... 24 more
Caused by: java.lang.StringIndexOutOfBoundsException: String index out of range: 0
at java.lang.String.charAt(String.java:687)
at org.hibernate.type.CharacterType.get(CharacterType.java:29)
at org.hibernate.type.NullableType.nullSafeGet(NullableType.java:163)
at org.hibernate.type.NullableType.nullSafeGet(NullableType.java:154)
at org.hibernate.type.AbstractType.hydrate(AbstractType.java:81)
at org.hibernate.persister.entity.AbstractEntityPersister.hydrate(AbstractEntityPersister.java:2096)
at org.hibernate.loader.Loader.loadFromResultSet(Loader.java:1380)
at org.hibernate.loader.Loader.instanceNotYetLoaded(Loader.java:1308)
at org.hibernate.loader.Loader.getRow(Loader.java:1206)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:580)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.doList(Loader.java:2220)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2104)
at org.hibernate.loader.Loader.list(Loader.java:2099)
at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:378)
at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:338)
at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:172)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1121)
at org.hibernate.impl.QueryImpl.list(QueryImpl.java:79)
at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:65)
I tried to find differences between the table structures and to debug with no luck.
My feeling is that for some reason the persistence layer (Hibernate) doesn't map in the right way a db field.
Any hnt would be appreciated.
Flavio

Answer 1

I found at last.
My problem is due to a single character table field ; in both databases the field is void and, I don't know why, from sqlserver Hibernate maps it correctly while from mysql it causes the exception menthioned.
I solved the problem simply initializing the table field.
Anyway I'm surprised that Hibernate could not manage correctly this case.
I hope this could be useful for somebody.
Flavio