i m creating web application using servlel/jsp and as per the requirment i want to create thread.
below are the codes i have tried but with no success.
i have created listener so that it got invoked when application starts.
ThreadListener.java
@WebListener
public class NewsCrawlerThreadListener implements ServletContextListener {
private ScheduledExecutorService scheduler = null;
@Override
public void contextInitialized(ServletContextEvent sce) {
if ((scheduler == null) || (!scheduler.isTerminated())) {
scheduler = Executors.newSingleThreadScheduledExecutor();
scheduler.scheduleAtFixedRate(new DemoThread(), 0, 2, TimeUnit.SECONDS);
}
}
@Override
public void contextDestroyed(ServletContextEvent sce) {
try {
System.out.println("Scheduler Shutting down successfully " + new Date());
scheduler.shutdown();
} catch (Exception ex) {
System.out.println("ERROR IN THREAD ->" + ex.getMessage());
}
}
}
Demo Thread
public class DemoThread implements Runnable {
public DemoThread() {
}
@Override
public void run() {
System.out.println("THREAD START :" + new Date());
// TODO
HttpClient httpclient = HttpClients.createDefault();
try {
URIBuilder builder = new URIBuilder("https://api.cognitive.microsoft.com/bing/");
builder.setParameter("mkt", "en-IN");
URI uri = builder.build();
HttpGet request = new HttpGet(uri);
request.setHeader("Ocp-Apim-Subscription-Key", "<api-key>");
// Request body
HttpResponse response = httpclient.execute(request);
HttpEntity entity = response.getEntity();
if (entity != null) {
JSONObject jsonObj = new JSONObject(EntityUtils.toString(entity));
JSONArray list = jsonObj.getJSONArray("value");
for (int i = 0; i < list.length(); i++) {
JSONObject oj = (JSONObject) list.get(i);
System.out.println(oj.get("name"));
System.out.println(oj.get("description") + "\n");
}
}
System.out.println("THREAD END :" + new Date());
} catch (Exception e) {
System.out.println("Exception in Thread :" + e.getMessage());
}
}
}
below is the stack trace when i run application
15-Nov-2016 19:22:41.775 SEVERE [localhost-startStop-1] org.apache.catalina.core.StandardContext.listenerStart Exception sending context initialized event to listener instance of class listener.NewsCrawlerThreadListener
java.lang.NoClassDefFoundError: org/apache/http/Consts
at org.apache.http.client.utils.URIBuilder.digestURI(URIBuilder.java:181)
at org.apache.http.client.utils.URIBuilder.<init>(URIBuilder.java:82)
at crawling.NewsCrawl.<init>(NewsCrawl.java:33)
at listener.NewsCrawlerThreadListener.contextInitialized(NewsCrawlerThreadListener.java:30)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4738)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5181)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:725)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:701)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:717)
at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:586)
at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1780)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassNotFoundException: org.apache.http.Consts
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1333)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1167)
... 17 more
15-Nov-2016 19:22:55.057 SEVERE [http-nio-8084-exec-10] org.apache.catalina.core.StandardContext.listenerStart Exception sending context initialized event to listener instance of class listener.NewsCrawlerThreadListener
java.lang.NoClassDefFoundError: org/apache/http/Consts
at org.apache.http.client.utils.URIBuilder.digestURI(URIBuilder.java:181)
at org.apache.http.client.utils.URIBuilder.<init>(URIBuilder.java:82)
at crawling.NewsCrawl.<init>(NewsCrawl.java:33)
at listener.NewsCrawlerThreadListener.contextInitialized(NewsCrawlerThreadListener.java:30)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4738)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5181)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:725)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:701)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:717)
at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:586)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:460)
at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1586)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:300)
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
at org.apache.catalina.manager.ManagerServlet.check(ManagerServlet.java:1460)
at org.apache.catalina.manager.ManagerServlet.deploy(ManagerServlet.java:906)
at org.apache.catalina.manager.ManagerServlet.doGet(ManagerServlet.java:344)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:217)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:614)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:673)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassNotFoundException: org.apache.http.Consts
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1333)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1167)
... 52 more
Web application is running fine but the thread i have created is not getting invoked. i don't know what is the problem in my code.
any help would be highly appreciated
EDIT
Thanks for your reply.
just solved it including proper version of the jar file. changed httpcore-4.2.1.jar to httpcore-4.4.4.jar and problem solved.
