title: JasperReport gets NullPointerException when detail band takes Split Type as Prevent
body: <p><em>Environment:</em></p>
  
  <ul>
  <li>Jboss 5.2</li>
  <li>Javaee 6</li>
  <li>JasperReport 6.5.1</li>
  </ul>
  
  <p>I'm getting a NullPointerError in JasperReport classes when I use in a detail band the Split Type = Prevent but when I use Split Type = NULL works well.</p>
  
  <p><strong>Report</strong></p>
  
  <pre><code>...
  &lt;band height="101" splitType="Prevent"&gt;
              &lt;subreport&gt;
                  &lt;reportElement x="0" y="27" width="555" height="70" uuid="f3948499-a572-4d2c-82ab-b24760874e7d"/&gt;
                  &lt;subreportParameter name="refCurs"&gt;
                      &lt;subreportParameterExpression&gt;&lt;![CDATA[$F{referenciacurs}]]&gt;&lt;/subreportParameterExpression&gt;
                  &lt;/subreportParameter&gt;
                  &lt;connectionExpression&gt;&lt;![CDATA[$P{REPORT_CONNECTION}]]&gt;&lt;/connectionExpression&gt;
                  &lt;subreportExpression&gt;&lt;![CDATA[$P{217_subParticipants}]]&gt;&lt;/subreportExpression&gt;
              &lt;/subreport&gt;
  ...
  </code></pre>
  
  <p><strong>Error trace</strong></p>
  
  <pre><code>2018-09-20 14:41:37,049 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[localhost].[/accforback].[Faces Servlet]] (http-10.215.15.23-8080-6) Servlet.service() para servlet Faces Servlet lanzó excepción
  java.lang.NullPointerException
      at net.sf.jasperreports.engine.fill.JRFillTextElement.setPrintText(JRFillTextElement.java:1057)
      at net.sf.jasperreports.engine.fill.JRFillStaticText.fill(JRFillStaticText.java:215)
      at net.sf.jasperreports.engine.fill.JRFillElementContainer.fillElements(JRFillElementContainer.java:1039)
      at net.sf.jasperreports.engine.fill.JRFillBand.fill(JRFillBand.java:454)
      at net.sf.jasperreports.engine.fill.JRFillBand.fill(JRFillBand.java:413)
      at net.sf.jasperreports.engine.fill.JRFillBand.refill(JRFillBand.java:385)
      at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillColumnBand(JRVerticalFiller.java:2608)
      at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillDetail(JRVerticalFiller.java:791)
      at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReportStart(JRVerticalFiller.java:252)
      at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReport(JRVerticalFiller.java:99)
      at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:609)
      at net.sf.jasperreports.engine.fill.BaseReportFiller.fill(BaseReportFiller.java:387)
      at net.sf.jasperreports.engine.fill.JRFiller.fill(JRFiller.java:109)
      at net.sf.jasperreports.engine.JasperFillManager.fill(JasperFillManager.java:456)
      at net.sf.jasperreports.engine.JasperFillManager.fillReport(JasperFillManager.java:863)
      at es.app.play.back.util.ReportManager.enviaDatos(ReportManager.java:140)
      at es.app.play.back.util.ReportManager.run(ReportManager.java:64)
      at es.app.play.back.controller.informes.ExecutarInformeController.compileReport(ExecutarInformeController.java:243)
      at es.app.play.back.controller.informes.ExecutarInformeController.report(ExecutarInformeController.java:114)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:606)
      at org.apache.el.parser.AstValue.invoke(AstValue.java:170)
      at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:276)
      at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
      at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:88)
      at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
      at javax.faces.component.UICommand.broadcast(UICommand.java:315)
      at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794)
      at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259)
      at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
      at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
      at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
      at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:103)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at es.app.play.back.filter.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:21)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:235)
      at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
      at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:183)
      at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:534)
      at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:95)
      at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126)
      at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70)
      at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
      at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
      at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)
      at es.caib.loginModule.auth.FormResourcesValve.invoke(FormResourcesValve.java:31)
      at es.caib.loginModule.auth.ClientIPValve.invoke(ClientIPValve.java:62)
      at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
      at org.jboss.web.tomcat.service.request.ActiveRequestResponseCacheValve.internalProcess(ActiveRequestResponseCacheValve.java:74)
      at org.jboss.web.tomcat.service.request.ActiveRequestResponseCacheValve.invoke(ActiveRequestResponseCacheValve.java:47)
      at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)
      at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829)
      at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:599)
      at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:451)
      at java.lang.Thread.run(Thread.java:745)
  </code></pre>