一个JSP页面的错误，不知道哪错了，求大神来看看
严重: Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
at org.apache.jsp.pic_jsp._jspService(pic_jsp.java:74)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:859)
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:579)
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1555)
at java.lang.Thread.run(Thread.java:619)
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@page import="org.jbpm.api.*,java.util.*,org.jbpm.api.model.*" %>
<%
String id = request.getParameter("id");
ProcessEngine processEngine = Configuration.getProcessEngine();
RepositoryService repositoryService = processEngine.getRepositoryService();
ExecutionService executionService = processEngine.getExecutionService();
ProcessInstance processInstance = executionService.findProcessInstanceById(id);
Set<String> activityNames = processInstance.findActiveActivityNames();
ActivityCoordinates ac = repositoryService.getActivityCoordinates(processInstance.getProcessDefinitionId(),activityNames.iterator().next());
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<img src="pic.jsp?id=<%=id%>" style="position:absolute;left:0px;top:0px;">
<div style="position:absolute;border:1px solid red;left:<%=ac.getX()%>px;top:<%=ac.getY()%>px;width:<%=ac.getWidth()%>px;height:<%=ac.getHeight()%>px;"></div>
</body>
</html>
<%@page import="org.jbpm.api.*,java.io.*"%>JSP Java String HTML
<%
ProcessEngine processEngine = Configuration.getProcessEngine();
RepositoryService repositoryService = processEngine
.getRepositoryService();
ExecutionService executionService = processEngine
.getExecutionService();
String id = request.getParameter("id");
ProcessInstance processInstance = executionService
.findProcessInstanceById(id);
String processDefinitionId = processInstance
.getProcessDefinitionId();
ProcessDefinition processDefinition = repositoryService
.createProcessDefinitionQuery().processDefinitionId(
processDefinitionId).uniqueResult();
InputStream inputStream = repositoryService.getResourceAsStream(processDefinition.getDeploymentId(),"leave.png");
byte[] b = new byte[1024];
int len = -1;
while ((len = inputStream.read(b, 0, 1024)) != -1) {
response.getOutputStream().write(b, 0, len);
}
%>
