为什么jsp中总是出现“超出GC开销限制，有时出现堆大小”错误？[副本]

Question

为什么我总是在JSP中遇到这个错误？

超过GC开销限制，有时堆大小

我正在使用Netbean IDE构建铁路票务网络应用程序。我被这个错误困住了。我尝试使用glassfishXX： MaxPermsize和Xmx的JVM设置来修复它。这个页面创建了很多对象，这个页面是为了生成一个随机的10位数机票号码并确认预订。

<table border="0" cellspacing="0" cellpadding="0" width="440">
<tr>
<td class="pageHeader"></td>
</tr>
<tr>
    <td class="bodyText" style="font-size:10pt"><p>  You have successfully booked your ticket !!
    <%@ page language="java" import="java.sql.*, java.io.*, java.lang.*,java.util.*,java.math.*" %>
    <%
        String bookinfo = request.getParameter("info");
        String args[] = bookinfo.split(",");
        int Trainno = Integer.parseInt(args[0]);
        String Trainname = args[1];
        java.sql.Date Dat = java.sql.Date.valueOf(args[2]);
        String tclass = args[3];
        String From = args[4];
        String To = args[5];
        int Distance = Integer.parseInt(args[6]);
        int Fare = Integer.parseInt(args[7]);
        int seats = Integer.parseInt(args[8]);
        String pname = request.getParameter("pname");
        int age = Integer.parseInt(request.getParameter("age"));
        String sex = request.getParameter("sex");
        int coach = 0, seatno = 0;
        String coachno = new String();
        double range = 10000000000.0;
        Random ran = new Random();
        int PNRno = 0;
        String PNR;
        int flag = 0, flag2 = 0;

   try 
    {
       Class.forName("oracle.jdbc.driver.OracleDriver"); // Oracle Driver
    } 
   catch (java.lang.ClassNotFoundException e) 
   {
       System.out.println("ClassNotFoundException: " + e.getMessage());
   }
       Connection con;
       PreparedStatement ps;
       PreparedStatement ps2;
       ResultSet rs, rs2;
       con = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521/XE", "system", "hr");
       String insertStmt2 = "SELECT PNRno,COACH,SEATNO FROM BOOKING WHERE STATUS = ? AND CLASS = ? AND COACH NOT LIKE ?";
       ps2 = con.prepareStatement(insertStmt2);
       ps2.setString(1, "CANCEL");
       ps2.setString(2, tclass);
       ps2.setString(3, "WL%");
       rs2 = ps2.executeQuery();
       if (rs2.next()) 
       {
               PNR = rs2.getString(1);
               coachno = rs2.getString(2);
               seatno = rs2.getInt(3);
               insertStmt2 = "DELETE FROM BOOKING WHERE PNRno = ?";
               ps2 = con.prepareStatement(insertStmt2);
               ps2.setString(1, PNR);
               rs2 = ps2.executeQuery();
               if (rs2.next()) 
               {
                   flag2 = 1;
               }
       }
           String insertStmt = "INSERT INTO BOOKING VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)";
           do 
           {
               ps = con.prepareStatement(insertStmt);
               PNRno = (int) ((ran.nextDouble()) * range);
               ps.setString(1, String.valueOf(PNRno));
               ps.setInt(2, Trainno);
               ps.setString(3, Trainname);
               ps.setDate(4, Dat);
               ps.setString(5, tclass);
               ps.setString(6, From);
               ps.setString(7, To);
               ps.setInt(8, Distance);
               ps.setInt(9, Fare);
               ps.setString(10, pname);
               ps.setInt(11, age);
               ps.setString(12, sex);
               if (seats > 0 && flag2 == 0) 
               {
                   coach = (seats - 1) / 60 + 1;
                   seatno = ((seats - 1) % 60) + 1;
                   ps.setInt(16, 0);
                   if (tclass.equals("SL")) {
                       coachno = String.valueOf("S" + coach);
                   } 
                   else if (tclass.equals("2A")) {
                       coachno = String.valueOf("A" + coach);
                   } 
                   else if (tclass.equals("3A")) {
                       coachno = String.valueOf("B" + coach);
                   } 
                   else {
                       coachno = String.valueOf("AC" + coach);
                   }
                   ps.setString(13, coachno);
                   ps.setInt(14, seatno);
                   ps.setString(15, "CONFIRM");
               } 
               else if (flag2 == 0) {
                   ps.setInt(16, (Math.abs(seats) + 1));
                   ps.setString(13, "WL" + String.valueOf((Math.abs(seats) + 1)));
                   ps.setInt(14, 0);
                   ps.setString(15, "WAITING");
               } 
               else {
                   ps.setString(13, coachno);
                   ps.setInt(14, seatno);
                   ps.setString(15, "CONFIRM");
                   ps.setInt(16, 0);
                }
               try {
                   flag = 0;
                   rs = ps.executeQuery();
               } 
               catch (SQLException e) {
                   flag = 1;
               }
           } 
           while (flag == 1);
               if (tclass.equals("SL")) {
                   insertStmt = "UPDATE SEATS SET \"SL\" = ? WHERE dat = ? AND trainno = ?";
               } else if (tclass.equals("1A")) {
                   insertStmt = "UPDATE SEATS SET \"1A\" = ? WHERE dat = ? AND trainno = ?";
               } else if (tclass.equals("2A")) {
                   insertStmt = "UPDATE SEATS SET \"2A\" = ? WHERE dat = ? AND trainno = ?";
               } else if (tclass.equals("3A")) {
                   insertStmt = "UPDATE SEATS SET \"3A\" = ? WHERE dat = ? AND trainno = ?";
               } else {
                   insertStmt = "UPDATE SEATS SET \"1C\" = ? WHERE dat = ? AND trainno = ?";
               }
           seats--;
           ps = con.prepareStatement(insertStmt);
           ps.setInt(1, seats);
           ps.setDate(2, Dat);
           ps.setInt(3, Trainno);
           try 
           {
               rs = ps.executeQuery();
               rs.close();
           } 
           catch (SQLException e) 
           {
           }
           finally
           {
                /*try
                {
                    rs.close();
                }
                catch(SQLException e){}*/
                try
                {
                    ps.close();   
                } 
                catch(SQLException e){}
                    con.close();                         
            }                          
    %>
        <form action="PNRHandler.jsp" method="get">

            <input type="hidden" name="PNR" value="<%=PNRno%>" size="20" />               
            <br>
            <input type="submit" name="Get Status" value="Get e-ticket">
        </form>                           
        </p>
        <br />      </td>
        <tr>
    </table>

Severe:   An exception or error occurred in the container during the request processing
java.lang.OutOfMemoryError: Java heap space
    at java.util.LinkedList.listIterator(LinkedList.java:868)
    at java.util.AbstractList.listIterator(AbstractList.java:299)
    at java.util.AbstractSequentialList.iterator(AbstractSequentialList.java:239)
    at org.apache.catalina.connector.CoyoteAdapter.enteringServletContainer(CoyoteAdapter.java:295)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:394)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283)
    at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
    at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206)
    at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180)
    at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
    at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111)
    at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
    at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536)
    at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
    at java.lang.Thread.run(Thread.java:745)

Severe:   doSelect exception
java.lang.OutOfMemoryError: Java heap space
    at java.util.ArrayList.iterator(ArrayList.java:834)
    at sun.nio.ch.WindowsSelectorImpl.updateSelectedKeys(WindowsSelectorImpl.java:496)
    at sun.nio.ch.WindowsSelectorImpl.doSelect(WindowsSelectorImpl.java:172)
    at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86)
    at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97)
    at org.glassfish.grizzly.nio.DefaultSelectorHandler.select(DefaultSelectorHandler.java:113)
    at org.glassfish.grizzly.nio.SelectorRunner.doSelect(SelectorRunner.java:339)
    at org.glassfish.grizzly.nio.SelectorRunner.run(SelectorRunner.java:279)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
    at java.lang.Thread.run(Thread.java:745)

Warning:   StandardWrapperValve[jsp]: Servlet.service() for servlet jsp threw exception
java.lang.OutOfMemoryError: Java heap space
    at java.util.Arrays.copyOf(Arrays.java:3332)
    at java.lang.AbstractStringBuilder.expandCapacity(AbstractStringBuilder.java:137)
    at java.lang.AbstractStringBuilder.ensureCapacityInternal(AbstractStringBuilder.java:121)
    at java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:421)
    at java.lang.StringBuffer.append(StringBuffer.java:272)
    at oracle.jdbc.driver.OracleSql.handleODBC(OracleSql.java:1249)
    at oracle.jdbc.driver.OracleSql.parse(OracleSql.java:1192)
    at oracle.jdbc.driver.OracleSql.getSql(OracleSql.java:326)
    at oracle.jdbc.driver.OracleSql.getSqlBytes(OracleSql.java:661)
    at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:215)
    at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:58)
    at oracle.jdbc.driver.T4CPreparedStatement.executeForRows(T4CPreparedStatement.java:943)
    at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1075)
    at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3820)
    at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3867)
    at oracle.jdbc.driver.OraclePreparedStatementWrapper.executeQuery(OraclePreparedStatementWrapper.java:1502)
    at org.apache.jsp.BookHandler2_jsp._jspService(BookHandler2_jsp.java:205)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:111)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:411)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:473)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:377)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:416)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283)

Answer 1

如果您的应用程序在GC上花费了太多的时间，超出GC开销限制的情况就会出现。

这个错误意味着GC试图释放内存，但几乎无法完成任何事情。默认情况下，当JVM花费超过98%的总时间在GC上，并且在GC之后恢复不到2%的堆时，就会发生这种情况。

您需要检查应用程序并关闭资源，以便GC可以释放它们