I am reading Head First Servlets and JSP, where one servlet had code:
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
foo.Person p = new foo.Person("Evan");
req.setAttribute("person", p);
RequestDispatcher view = req.getRequestDispatcher("/result.jsp");
view.forward(req, resp);
}
Later on, they showed how to use <jsp:useBean> and <jsp:useProperty> to get person's name:
I thought I understand it - if there isn't attribute at request scope means variable person will be null, which also means new Person object using default constructor will be made. Bottom line: I won't have my attribute. Luckily, I previously stored Person object at request's scope, meaning it will find it.
So I wanted to try it out and change code a little. Instead of <jsp:useBean id="person" class="foo.Person" scope="request"/>, I typed <jsp:useBean id="person" class="foo.Person" scope="application"/>. Remember that our attribute is previously stored at request's scope and not application, meaning person will be null. To my surprise, it easily found the attribute and printed Evan. How did it happen, when book clearly showed that it will search for attribute at the same scope that I wrote in scope's attribute?
The key takeaway is that <jsp:useBean> can also create an object if it does not find one in the scope you specified. That means that:
if the object is not in the scope you said it was, <jsp:useBean> will create a new object.
if the object is in the scope you said it is, <jsp:useBean> will use that object.
In other words, you can deal with one object or with two, depending in which context you placed the object, and in which context you say it is.
I know, it's confusing. So let's play with some examples. I'm going to butcher the Person class a bit to show where objects get created.
package test;
public class Person {
private String name;
public Person() {
try {
throw new RuntimeException("Just to see what's going on");
} catch (RuntimeException ex) {
System.out.println(">>>>>>>>>>>>>>>>>>>>>>>>>");
for (StackTraceElement ste : ex.getStackTrace()) {
System.out.println(ste.toString());
}
System.out.println("<<<<<<<<<<<<<<<<<<<<<<<");
}
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
First example: scopes match
Servlet content:
public class TestController extends HttpServlet {
private static final long serialVersionUID = 1L;
#Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
HttpSession session = request.getSession();
session.setAttribute("person", new Person());
RequestDispatcher requestDispatcher = request.getRequestDispatcher("/test.jsp");
requestDispatcher.forward(request, response);
}
}
test.jsp:
<%# page contentType="text/html; charset=UTF-8" %>
<!DOCTYPE html>
<html>
<body>
<jsp:useBean id="person" class="test.Person" scope="session" />
</body>
</html>
Accessing the servlet will cause this output:
>>>>>>>>>>>>>>>>>>>>>>>>>
test.Person.<init>(Person.java:8)
test.TestController.doGet(TestController.java:21)
javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:744)
<<<<<<<<<<<<<<<<<<<<<<<
Look at the first two lines and you will see only one object is created, inside the servlet. The <jsp:useBean> just retrieves this one.
Second example: scopes do not match
Servlet stays the same:
public class TestController extends HttpServlet {
private static final long serialVersionUID = 1L;
#Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
HttpSession session = request.getSession();
session.setAttribute("person", new Person());
RequestDispatcher requestDispatcher = request.getRequestDispatcher("/test.jsp");
requestDispatcher.forward(request, response);
}
}
The JSP now uses application scope, instead of session scope where the actual person is located:
<%# page contentType="text/html; charset=UTF-8" %>
<!DOCTYPE html>
<html>
<body>
<jsp:useBean id="person" class="test.Person" scope="application" />
</body>
</html>
The result is now this:
>>>>>>>>>>>>>>>>>>>>>>>>>
test.Person.<init>(Person.java:8)
test.TestController.doGet(TestController.java:21)
javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:744)
<<<<<<<<<<<<<<<<<<<<<<<
>>>>>>>>>>>>>>>>>>>>>>>>>
test.Person.<init>(Person.java:8)
org.apache.jsp.test_jsp._jspService(test_jsp.java:71)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:748)
org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:486)
org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:411)
org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:338)
test.TestController.doGet(TestController.java:24)
javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:744)
<<<<<<<<<<<<<<<<<<<<<<<
You now have two objects. One created by the servlet, as in the first example, but also another one that gets created by the JSP's generated servlet, because <jsp:useBean> couldn't find an object in application scope, so it used the class attribute to create one.
The confusion is caused by <jsp:getProperty> which searches for an object in scopes page > request > session > application, until it finds one. This is separate from what <jsp:useBean> does (as described above with the two examples).
When in doubt, refer to the JSP specs.
With that being said, note that <jsp:useBean> and <jsp:getProperty> aren't really very much used in practice. People use the JSP expression language, JSTL, or other (more powerful) custom tags. For the purpose of learning from a book and avoiding to use scriptlets (that are a bad practice), these are fine to get you started, but in practice they are not really people's favorite way of accessing objects and their properties.
Check the following description of <jsp:getProperty> from JavaServer Pages™Specification
The value of the name attribute in jsp:setProperty and jsp:getProperty
will refer to an object that is obtained from the pageContext object
through its findAttribute method.
And now, check the description of findAttribute in the same document:
Searches for the named attribute
in page, request, session (if valid), and application scope(s) in
order and returns the value associated or null.
Thus, if the attribute, person is not found in the request scope, the search is expanded up to application scope.
<jsp:useBean id="person" class="foo.Person" scope="application"/> will create a new Person and put it into application scope if does not exist there irrespective of whether this attribute already exists in request scope.
When you use <jsp:getProperty name="person" property="name">, the search for the attribute, person will be performed on page > request > session (if valid) > application scope(s) in sequence and in a find-first approach i.e. as soon as it is found, the value is returned (i.e. no further search happens).
Since you have two Person objects with the attribute named as person: one with the name, Evan in the request scope, and another as a new Person() in the application scope, the one in the request scope is returned as a result of the way how findAttribute works.
I am getting following exception while uploading a file using Apache common uploadFile. I am able to upload small file less then 3mb. When i try to upload large file following error occors
rg.apache.commons.fileupload.FileUploadBase$IOFileUploadException: Processing of multipart/form-data request failed. Unexpected EOF read on the socket
at org.apache.commons.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:371)
at org.apache.commons.fileupload.servlet.ServletFileUpload.parseRequest(ServletFileUpload.java:126)
at org.apache.jsp.fileUpload_jsp._jspService(fileUpload_jsp.java:1058)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:610)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:683)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1725)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1683)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1152)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:622)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.io.EOFException: Unexpected EOF read on the socket
at org.apache.coyote.http11.InternalNioInputBuffer.readSocket(InternalNioInputBuffer.java:448)
at org.apache.coyote.http11.InternalNioInputBuffer.fill(InternalNioInputBuffer.java:800)
at org.apache.coyote.http11.InternalNioInputBuffer$SocketInputBuffer.doRead(InternalNioInputBuffer.java:825)
And this is how i am using apache upload
DiskFileItemFactory fileItemFactory = new DiskFileItemFactory ();
fileItemFactory.setSizeThreshold(5*1024*1024);
fileItemFactory.setRepository(tmpDir);
ServletFileUpload uploadHandler = new ServletFileUpload(fileItemFactory);
long fileSize = 0;
List items = uploadHandler.parseRequest(request);
Iterator itr = items.iterator();
I am developing a little webapp meant to be run on Tomcat. The webapp works fine on my Windows machine (Windows 7, Java 1.8, Tomcat 7) but fails to run on my raspberry pi 3 (Raspian with the lastest update, Java 1.8, Tomcat 7). Starting Tomcat is fine until one try to load the login page. Then I got the following output :
Error when loading localhost:8080/Timbreuse/connection
java.lang.NullPointerException
at ch.cpnv.timbreuse.servlets.Connection.doGet(Connection.java:39)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:748)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:486)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:411)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:338)
at ch.cpnv.timbreuse.filters.ConnectedFilter.doFilter(ConnectedFilter.java:39)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
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)
Message : null
java.lang.NullPointerException
at ch.cpnv.timbreuse.servlets.Connection.doGet(Connection.java:39)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:748)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:486)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:411)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:338)
at ch.cpnv.timbreuse.filters.ConnectedFilter.doFilter(ConnectedFilter.java:39)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
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)
Connection.java:39
public static final String VIEW_CONNECTION = "/WEB-INF/connection.jsp";
public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
this.getServletContext().getRequestDispatcher(VIEW_CONNECTION).forward(request, response);
}
Folder architecture when the .war is deployed on the Pi
./student
./student/info.jsp
./display
./display/welcomeDisplay.jsp
./display/showDisplay.jsp
./WEB-INF
./WEB-INF/header.jsp
./WEB-INF/changePassword.jsp
./WEB-INF/classes
./WEB-INF/classes/ch
./WEB-INF/classes/ch/cpnv
./WEB-INF/classes/ch/cpnv/timbreuse
./WEB-INF/classes/ch/cpnv/timbreuse/automation
./WEB-INF/classes/ch/cpnv/timbreuse/automation/Automation.java
./WEB-INF/classes/ch/cpnv/timbreuse/automation/Automation.class
./WEB-INF/classes/ch/cpnv/timbreuse/automation/EndOfDay$EndOfDayTask.class
./WEB-INF/classes/ch/cpnv/timbreuse/automation/EndOfDay.class
./WEB-INF/classes/ch/cpnv/timbreuse/automation/EndOfDay.java
./WEB-INF/classes/ch/cpnv/timbreuse/forms
./WEB-INF/classes/ch/cpnv/timbreuse/forms/AddTimeStudentsForm.class
./WEB-INF/classes/ch/cpnv/timbreuse/forms/CreateStudentForm.java
./WEB-INF/classes/ch/cpnv/timbreuse/forms/ChangePasssowordForm.java
./WEB-INF/classes/ch/cpnv/timbreuse/forms/CreateStudentForm.class
./WEB-INF/classes/ch/cpnv/timbreuse/forms/StudentResearchForm.class
./WEB-INF/classes/ch/cpnv/timbreuse/forms/AddTimeStudentsForm.java
./WEB-INF/classes/ch/cpnv/timbreuse/forms/CreateAdminForm.class
./WEB-INF/classes/ch/cpnv/timbreuse/forms/DeleteStudentForm.class
./WEB-INF/classes/ch/cpnv/timbreuse/forms/ConnectionForm.java
./WEB-INF/classes/ch/cpnv/timbreuse/forms/DeleteStudentForm.java
./WEB-INF/classes/ch/cpnv/timbreuse/forms/DeleteTeacherForm.class
./WEB-INF/classes/ch/cpnv/timbreuse/forms/ChangePasssowordForm.class
./WEB-INF/classes/ch/cpnv/timbreuse/forms/StudentResearchForm.java
./WEB-INF/classes/ch/cpnv/timbreuse/forms/DeleteAdminForm.java
./WEB-INF/classes/ch/cpnv/timbreuse/forms/CreateTeacherForm.class
./WEB-INF/classes/ch/cpnv/timbreuse/forms/DeleteAdminForm.class
./WEB-INF/classes/ch/cpnv/timbreuse/forms/ConnectionForm.class
./WEB-INF/classes/ch/cpnv/timbreuse/forms/SetHolydaysForm.java
./WEB-INF/classes/ch/cpnv/timbreuse/forms/CreateAdminForm.java
./WEB-INF/classes/ch/cpnv/timbreuse/forms/CreateTeacherForm.java
./WEB-INF/classes/ch/cpnv/timbreuse/forms/SetHolydaysForm.class
./WEB-INF/classes/ch/cpnv/timbreuse/forms/DeleteTeacherForm.java
./WEB-INF/classes/ch/cpnv/timbreuse/beans
./WEB-INF/classes/ch/cpnv/timbreuse/beans/Teacher.class
./WEB-INF/classes/ch/cpnv/timbreuse/beans/Teacher.java
./WEB-INF/classes/ch/cpnv/timbreuse/beans/Student.class
./WEB-INF/classes/ch/cpnv/timbreuse/beans/Student.java
./WEB-INF/classes/ch/cpnv/timbreuse/beans/Log.class
./WEB-INF/classes/ch/cpnv/timbreuse/beans/Log.java
./WEB-INF/classes/ch/cpnv/timbreuse/beans/User.class
./WEB-INF/classes/ch/cpnv/timbreuse/beans/Holyday.java
./WEB-INF/classes/ch/cpnv/timbreuse/beans/Holyday.class
./WEB-INF/classes/ch/cpnv/timbreuse/beans/User.java
./WEB-INF/classes/ch/cpnv/timbreuse/config
./WEB-INF/classes/ch/cpnv/timbreuse/config/DAOFactoryInitialisation.class
./WEB-INF/classes/ch/cpnv/timbreuse/config/DAOFactoryInitialisation.java
./WEB-INF/classes/ch/cpnv/timbreuse/dao
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOUtility.class
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOImplUser.class
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOImplTeacher.java
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOUser.class
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOLog.class
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOStudent.java
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOUtility.java
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOTeacher.java
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOException.java
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOImplStudent.class
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOImplTeacher.class
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOImplHolyday.class
./WEB-INF/classes/ch/cpnv/timbreuse/dao/dao.properties
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOImplUser.java
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOImplHolyday.java
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOFactory.java
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOImplLog.class
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOImplAdmin.class
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOImplStudent.java
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOHolyday.class
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOFactory.class
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOTeacher.class
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOImplAdmin.java
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOException.class
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOUser.java
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOHolyday.java
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOLog.java
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOStudent.class
./WEB-INF/classes/ch/cpnv/timbreuse/dao/DAOImplLog.java
./WEB-INF/classes/ch/cpnv/timbreuse/servlets
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/SetTimetable.class
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/AdminPanel.java
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/Display.java
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/Connection.java
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/Logout.class
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/SetTimetable.java
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/ChangePassword.java
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/Logout.java
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/SetHolydays.class
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/AdminPanel.class
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/StudentInfo.java
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/ChangePassword.class
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/EndDay.class
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/ManageStudents.java
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/ManageStudents.class
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/Display.class
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/Connection.class
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/EndDay.java
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/StudentInfo.class
./WEB-INF/classes/ch/cpnv/timbreuse/servlets/SetHolydays.java
./WEB-INF/classes/ch/cpnv/timbreuse/mathTime
./WEB-INF/classes/ch/cpnv/timbreuse/mathTime/Math.class
./WEB-INF/classes/ch/cpnv/timbreuse/mathTime/Math.java
./WEB-INF/classes/ch/cpnv/timbreuse/mathTime/Date.class
./WEB-INF/classes/ch/cpnv/timbreuse/mathTime/SecondsPastMidnight.class
./WEB-INF/classes/ch/cpnv/timbreuse/mathTime/SecondsPastMidnight.java
./WEB-INF/classes/ch/cpnv/timbreuse/mathTime/Date.java
./WEB-INF/classes/ch/cpnv/timbreuse/filters
./WEB-INF/classes/ch/cpnv/timbreuse/filters/ConnectedFilter.class
./WEB-INF/classes/ch/cpnv/timbreuse/filters/ConnectionFilter.class
./WEB-INF/classes/ch/cpnv/timbreuse/filters/StudentFilter.class
./WEB-INF/classes/ch/cpnv/timbreuse/filters/TeacherFilter.java
./WEB-INF/classes/ch/cpnv/timbreuse/filters/ConnectionFilter.java
./WEB-INF/classes/ch/cpnv/timbreuse/filters/AdminFilter.java
./WEB-INF/classes/ch/cpnv/timbreuse/filters/AdminFilter.class
./WEB-INF/classes/ch/cpnv/timbreuse/filters/ConnectedFilter.java
./WEB-INF/classes/ch/cpnv/timbreuse/filters/TeacherFilter.class
./WEB-INF/classes/ch/cpnv/timbreuse/filters/StudentFilter.java
./WEB-INF/footer.jsp
./WEB-INF/.gitignore
./WEB-INF/lib
./WEB-INF/lib/bonecp-0.8.1-20131105.191813-1.jar
./WEB-INF/lib/jasypt-1.9.0.jar
./WEB-INF/lib/jstl-1.2.jar
./WEB-INF/lib/java-json.jar
./WEB-INF/lib/slf4j-api-1.6.6.jar
./WEB-INF/lib/joda-time-2.1.jar
./WEB-INF/lib/mysql-connector-java-5.1.38-bin.jar
./WEB-INF/lib/guava-13.0.1.jar
./WEB-INF/web.xml
./WEB-INF/connection.jsp
./connecting.jsp
./form.css
./META-INF
./META-INF/MANIFEST.MF
./teacher
./teacher/setTimeTable.jsp
./teacher/manageStudents.jsp
./teacher/setHolydays.jsp
./admin
./admin/adminPanel.jsp
How can I prevent that ?
The only objects that can be null are request and response, or dispatcher. If you can't place a breakpoint there, I would check tomcat's messages/logs before the exception
I am using tomcat 7 and wanted to run my API on it.
I have read that TomEE was the way to do this. However when I put the TomEE "Drop in War" and I try to run my API on TomEE, all request that use an injected service throw a nullpointer.
Using the following request works
#GET
#Path("/test")
public String gettest() {
return "TEST";
}
But using the following returns a NullPointerException
#EJB(beanName = "service")
IService thisservice;
#GET
#Path("/call")
#Produces("application/xml, application/json")
public List<MyObject> getAllObjects() {
List<MyObject> objects= thisservice.findAllObjects();
return objects;
}
The class service that I wanna use looks like this
#Stateless(name = "service")
public class ServiceImpl implements IService {
#Override
public List<MyObject> findAllObjects() {
List<MyObject> objects = new ArrayList();
return objects;
}
}
The exception I get
Nov 09, 2015 5:21:23 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [com.catcode.web.api.rest.ApplicationConfig] in context with path [/web-api-jersey-5.0] threw exception [java.lang.NullPointerException] with root cause
java.lang.NullPointerException
at com.catcode.web.api.rest.resources.MyResource.getAllObjects(MyResource.java:40)
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:606)
at org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory$1.invoke(ResourceMethodInvocationHandlerFactory.java:81)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher$1.run(AbstractJavaResourceMethodDispatcher.java:151)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java:171)
at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$TypeOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:195)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:104)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:384)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:342)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:101)
at org.glassfish.jersey.server.ServerRuntime$1.run(ServerRuntime.java:271)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:271)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:267)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:297)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:254)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1030)
at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:373)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:381)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:344)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:221)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:957)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:620)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
Hope that someone can help me with this!
I am currently working on a small addresstable with vaadin, just to get to know vaadin a little. I have run into a problem, where I want to sort the entries of my table manually. The problem is, that I get a NullPointerException when i try to do this:
item.getItemProperty(Columns.NAME).getValue()
I have tried a few things here. I checked item and item isn't null, neither is item.getItemProperty(Columns.NAME) null. So when I try to make an if I still get a NullPointerException
if(item.getItemProperty(Columns.NAME).getValue() == null){}
The value is null and I understand that, but I want to give this value to an other item and I have no idea how to.
SEVERE: Servlet.service() for servlet [com.example.addresstable.AddresstableUI$Servlet] in context with path [/Addresstable] threw exception [com.vaadin.server.ServiceException: java.lang.NullPointerException] with root cause
java.lang.NullPointerException
at com.vaadin.data.util.IndexedContainer$IndexedContainerProperty.getValue(IndexedContainer.java:898)
at com.example.addresstable.AddressTable.addAddressToTable(AddressTable.java:114)
at com.example.addresstable.AddresstableUI.init(AddresstableUI.java:26)
at com.vaadin.ui.UI.doInit(UI.java:639)
at com.vaadin.server.communication.UIInitHandler.getBrowserDetailsUI(UIInitHandler.java:222)
at com.vaadin.server.communication.UIInitHandler.synchronizedHandleRequest(UIInitHandler.java:74)
at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41)
at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1402)
at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:305)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
IndexedContainer's Items are IndexedContainerItem.
When call it's getItemProperty the result is never null:
#Override
public Property getItemProperty(Object id) {
return new IndexedContainerProperty(itemId, id);
}
But when you call Property's getValue it may be null if there is no itemId or propertyId:
#Override
public T getValue() {
return (T) items.get(itemId).get(propertyId);
}
Probably it is a Vaadin bug: link
EDIT
If you want to check the container contains the item, you can do this:
public class MyIndexedContainer extends IndexedContainer {
#Override
public Item getUnfilteredItem(Object itemId) { // make it public
return super.getUnfilteredItem(itemId);
}
}
then
Table table = new Table();
MyIndexedContainer mic = new MyIndexedContainer();
table.setContainerDataSource(mic);
//...
// check that the container contains the item
if (mic.getUnfilteredItem(item) != null) {
//...
}