由于添加功能导致Java堆空间错误

Question

Whenever I am calling the getFriendList function from the xhtml page I am getting an exception. The page keeps on loading and after that I stop the browser. I get the given stackstrace. Its is telling me that there is an error at line no.78 friends.add(friend); . I think there is something wrong with my syntax. It would be helpful if someone point the error.

1)Here is my FriendBean it is request scoped.

package com.bean;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import javax.faces.context.FacesContext;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;
import javax.servlet.http.HttpSession;
import com.entity.Friend;
import com.entity.User;

public class FriendBean {

    Friend friend;
    private EntityManager em;
    public FriendBean(){
        friend = new Friend();
        EntityManagerFactory emf=Persistence.createEntityManagerFactory("FreeBird");
         em =emf.createEntityManager();
    }
    public Friend getFriend() {
        return friend;
    }
    public void setFriend(Friend friend) {
        this.friend = friend;
    }
    public List<Friend> getFriendRequestList(){
        FacesContext context = FacesContext.getCurrentInstance();
        HttpSession session = (HttpSession) context.getExternalContext().getSession(true);
        User user=(User) session.getAttribute("userdet");
        Query query = em.createQuery("SELECT f FROM Friend f WHERE f.email='"+user.getEmail()+"' AND f.status=0",Friend.class);
          List<Friend> results =query.getResultList();
          return results;


    }
    public String friendAccept(String friendRequestId){

        System.out.println("friend accept called...");
        Friend f=em.find(Friend.class,Integer.parseInt(friendRequestId));
        f.setStatus(1);
        em.getTransaction().begin();
        em.persist(f);
        em.getTransaction().commit();
        Friend viceversa=new Friend();
        viceversa.setEmail(f.getFriendEmail());
        viceversa.setFriendEmail(f.getEmail());
        viceversa.setStatus(1);
        em.getTransaction().begin();
        em.persist(viceversa);
        em.getTransaction().commit();
        return "success";

    }
    public String friendReject(String friendRequestId){
        System.out.println("friend reject called..");
        Friend f = em.find(Friend.class,Integer.parseInt(friendRequestId));
        em.getTransaction().begin();
        em.remove(f);
        em.getTransaction().commit();
        return "success";
    }
    public List<User> getFriendList(){

        FacesContext context = FacesContext.getCurrentInstance();
        HttpSession session = (HttpSession) context.getExternalContext().getSession(true);
        User user=(User) session.getAttribute("userdet");
        Query query = em.createQuery("SELECT f FROM Friend f WHERE f.email='"+user.getEmail()+"' AND f.status=1",Friend.class);
         List<Friend> results =query.getResultList();
         ArrayList<User> friends = new ArrayList<User>();

         while(results.listIterator().hasNext()){
             User friend =em.find(User.class,results.listIterator().next().getFriendEmail());
             friends.add(friend);
         }
          return friends;

    }
}

2)Here is the exception that I am getting.

SEVERE: Error Rendering View[/Home.xhtml]
javax.el.ELException: /Home.xhtml @146,59 value="#{friendBean.friendList}": java.lang.OutOfMemoryError: Java heap space
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:114)
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
    at javax.faces.component.UIData.getValue(UIData.java:731)
    at javax.faces.component.UIData.getDataModel(UIData.java:1798)
    at javax.faces.component.UIData.setRowIndexWithoutRowStatePreserved(UIData.java:484)
    at javax.faces.component.UIData.setRowIndex(UIData.java:473)
    at com.sun.faces.renderkit.html_basic.TableRenderer.encodeBegin(TableRenderer.java:81)
    at javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:820)
    at javax.faces.component.UIData.encodeBegin(UIData.java:1118)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1755)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760)
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:402)
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
    at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1550)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:343)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
    at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:331)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
    at com.sun.enterprise.v3.services.impl.ContainerMapper$AdapterCallable.call(ContainerMapper.java:317)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
    at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:860)
    at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:757)
    at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1056)
    at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:229)
    at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
    at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
    at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
    at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
    at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
    at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.OutOfMemoryError: Java heap space
    at java.util.Arrays.copyOf(Arrays.java:2245)
    at java.util.Arrays.copyOf(Arrays.java:2219)
    at java.util.ArrayList.grow(ArrayList.java:213)
    at java.util.ArrayList.ensureCapacityInternal(ArrayList.java:187)
    at java.util.ArrayList.add(ArrayList.java:411)
    at com.bean.FriendBean.getFriendList(FriendBean.java:78)
    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:601)
    at javax.el.BeanELResolver.getValue(BeanELResolver.java:363)
    at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
    at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
    at com.sun.el.parser.AstValue.getValue(AstValue.java:138)
    at com.sun.el.parser.AstValue.getValue(AstValue.java:183)
    at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:224)
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
    at javax.faces.component.UIData.getValue(UIData.java:731)
    at javax.faces.component.UIData.getDataModel(UIData.java:1798)
    at javax.faces.component.UIData.setRowIndexWithoutRowStatePreserved(UIData.java:484)
    at javax.faces.component.UIData.setRowIndex(UIData.java:473)
    at com.sun.faces.renderkit.html_basic.TableRenderer.encodeBegin(TableRenderer.java:81)
    at javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:820)
    at javax.faces.component.UIData.encodeBegin(UIData.java:1118)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1755)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760)
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:402)
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
    at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)

WARNING: StandardWrapperValve[Faces Servlet]: PWC1406: Servlet.service() for servlet Faces Servlet threw exception
java.lang.OutOfMemoryError: Java heap space
    at java.util.Arrays.copyOf(Arrays.java:2245)
    at java.util.Arrays.copyOf(Arrays.java:2219)
    at java.util.ArrayList.grow(ArrayList.java:213)
    at java.util.ArrayList.ensureCapacityInternal(ArrayList.java:187)
    at java.util.ArrayList.add(ArrayList.java:411)
    at com.bean.FriendBean.getFriendList(FriendBean.java:78)
    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:601)
    at javax.el.BeanELResolver.getValue(BeanELResolver.java:363)
    at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
    at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
    at com.sun.el.parser.AstValue.getValue(AstValue.java:138)
    at com.sun.el.parser.AstValue.getValue(AstValue.java:183)
    at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:224)
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
    at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
    at javax.faces.component.UIData.getValue(UIData.java:731)
    at javax.faces.component.UIData.getDataModel(UIData.java:1798)
    at javax.faces.component.UIData.setRowIndexWithoutRowStatePreserved(UIData.java:484)
    at javax.faces.component.UIData.setRowIndex(UIData.java:473)
    at com.sun.faces.renderkit.html_basic.TableRenderer.encodeBegin(TableRenderer.java:81)
    at javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:820)
    at javax.faces.component.UIData.encodeBegin(UIData.java:1118)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1755)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760)
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:402)
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
    at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)

Answer 1

You are clearly running into an issue where your Tomcat server instance has not been allocated enough memory to the JVM heap space. An OutOfMemoryError will be thrown when the allocated heap space has been completely consumed.

You can allocate more through the Tomcat Windows application or you can set in catalina.bat or catalina.sh

Example:

set CATALINA_OPTS=-Xms512m -Xmx512m