sublist index out of bound exception

Question

Whenever I am running my xhtml. It is giving me the following exception. The value of statusindex object is 5. I am using JQuery for lazy scrolling,so when my xhml page getMoreStatusList calls getMoreStatusList function, it is giving me an index out of bound exception. There are 26 status updates in the database so index out of bound exception makes no sense to me.

1) Code

public List<Status> getMoreStatusList() {

    FacesContext context = FacesContext.getCurrentInstance();
    HttpSession session = (HttpSession) context.getExternalContext()
            .getSession(false);
    User user = (User) session.getAttribute("userdet");
    Query query = em.createQuery("SELECT s FROM Status s WHERE s.email='"
            + user.getEmail() + "' ORDER BY s.timeMillis desc",
            Status.class);
    List<Status> results = query.getResultList();
    Query query1 = em.createQuery("SELECT f FROM Friend f WHERE f.email='"
            + user.getEmail() + "'", Friend.class);
    List<Friend> results1 = query1.getResultList();
    Iterator<Friend> it = results1.listIterator();
    while (it.hasNext()) {
        String email = it.next().getFriendEmail();
        Query query2 = em.createQuery(
                "SELECT s FROM Status s WHERE s.email='" + email
                        + "' ORDER BY s.timeMillis desc", Status.class);
        List<Status> results2 = query2.getResultList();
        results.addAll(results2);

    }
    Collections.sort(results);
    int index = (int) session.getAttribute("statusindex");
    System.out.println(index);
    results = results.subList(index,index+5);
    session.setAttribute("statusindex", index + 5);
    return results;

}

2) Exception

Mar 02, 2013 9:31:58 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [Faces Servlet] in context with path [/FreeBird_v.6] threw exception [/getMoreStatusList.xhtml @120,43 test="#{p.videostatus!=null}" /getMoreStatusList.xhtml @120,43 test="#{p.videostatus!=null}": /getMoreStatusList.xhtml @14,60 items="#{statusBean.moreStatusList}": Error reading 'moreStatusList' on type com.bean.StatusBean] with root cause
java.lang.IndexOutOfBoundsException: toIndex = 30
    at java.util.SubList.<init>(Unknown Source)
    at java.util.RandomAccessSubList.<init>(Unknown Source)
    at java.util.AbstractList.subList(Unknown Source)
    at java.util.Vector.subList(Unknown Source)
    at com.bean.StatusBean.getMoreStatusList(StatusBean.java:190)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at javax.el.BeanELResolver.getValue(BeanELResolver.java:87)
    at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:67)
    at com.sun.faces.el.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:71)
    at org.apache.el.parser.AstValue.getValue(AstValue.java:169)
    at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:189)
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:106)
    at com.sun.faces.facelets.tag.jstl.core.IndexedValueExpression.getValue(IndexedValueExpression.java:89)
    at org.apache.el.parser.AstIdentifier.getValue(AstIdentifier.java:68)
    at org.apache.el.parser.AstValue.getValue(AstValue.java:147)
    at org.apache.el.parser.AstNotEqual.getValue(AstNotEqual.java:38)
    at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:189)
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:106)
    at com.sun.faces.facelets.tag.TagAttributeImpl.getObject(TagAttributeImpl.java:326)
    at com.sun.faces.facelets.tag.TagAttributeImpl.getBoolean(TagAttributeImpl.java:133)
    at com.sun.faces.facelets.tag.jstl.core.IfHandler.apply(IfHandler.java:88)
    at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:94)
    at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:131)
    at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:162)
    at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:114)
    at com.sun.faces.facelets.tag.jstl.core.ForEachHandler.apply(ForEachHandler.java:214)
    at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:131)
    at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:162)
    at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:114)
    at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:94)
    at com.sun.faces.facelets.compiler.NamespaceHandler.apply(NamespaceHandler.java:89)
    at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:94)
    at com.sun.faces.facelets.compiler.EncodingHandler.apply(EncodingHandler.java:79)
    at com.sun.faces.facelets.impl.DefaultFacelet.apply(DefaultFacelet.java:148)
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.buildView(FaceletViewHandlingStrategy.java:734)
    at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:96)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
    at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:135)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:309)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1001)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)

Answer 1

List.subList()'s documentation is very clear:

Throws: IndexOutOfBoundsException - for an illegal endpoint index value (fromIndex < 0 || toIndex > size || fromIndex > toIndex)

In your case, toIndex > size:

java.lang.IndexOutOfBoundsException: toIndex = 30