title: Getting NullPointerException trying to access "response" in JSP
body: <p>In a JSP page, when the user logs out, I'm deleting their login cookies using this code:</p>
  
  <pre><code>Cookie killMyCookie = new Cookie("cookie1", null);
  killMyCookie.setMaxAge(0);
  killMyCookie.setPath("/JSPLearn");
  response.addCookie(killMyCookie);
  killMyCookie = new Cookie("cookie2", null);
  killMyCookie.setMaxAge(0);
  killMyCookie.setPath("/JSPLearn");
  response.addCookie(killMyCookie);
  </code></pre>
  
  <p>After this, I'm calling</p>
  
  <pre><code>response.sendRedirect("index.jsp");
  </code></pre>
  
  <p>It's throwing a NullPointerException.</p>
  
  <p>Why would response be null?</p>
  
  <p>Stacktrace:</p>
  
  <pre><code>java.lang.NullPointerException
  at java.net.URLEncoder.encode(URLEncoder.java:205)
  at org.apache.jsp.index_jsp._jspService(index_jsp.java:175)
  at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:111)
  at javax.servlet.http.HttpServlet.service(HttpServlet.java:770)
  at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:403)
  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:770)
  at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1542)
  at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
  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$AdapterCallable.call(ContainerMapper.java:317)
  at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
  at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:849)
  at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:746)
  at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1045)
  at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:228)
  at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
  at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
  at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
  at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
  at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
  at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
  at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
  at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
  at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
  at java.lang.Thread.run(Thread.java:722)
  </code></pre>