Bizarre thread problem with JSP

Question

I'm having a strange problem using JSPs whereby a single method call to a
          bean results in 2 execute threads being created each executing the method
          called.
          I have a bean reference in the jsp that has session scope declared like this
          (package names left off):
          <jsp:useBean id="deployment" class="Deployment" scope="session">
          <% deployment.init(application); %>
          </jsp:useBean>
          I've also set the isThreadSafe value to "false" (since I'm trying to
          prevent/figure out what's going on):
          <%@ page isThreadSafe="false" %>
          Within the JSP body I have code that makes the method call on the deployment
          bean:
          if (action.equals("Send"))
          int status = deployment.send();
          Then, within my form I have:
          <INPUT TYPE="image" SRC="../images/Deploy.gif"
          onClick="confirmAndSubmit('Send',
          'Deploying Application to server <%=
          deployment.getServer() %>')"/>
          Where the functions called are:
          function setActionSubmit(action) {
          document.deployForm.actionPerformed.value = action;
          document.deployForm.submit();
          function confirmAndSubmit(action, promptString) {
          if (confirm(promptString)) {
          setActionSubmit(action);
          Tracing, thread dumping, et al, have confirmed that although I have a single
          session, I end up with two threads each executing the deployment.send()
          method.
          Any ideas? I'm stumped.
          Thanks,
          Jim
          

Answer 1

I found the problem, although I don't completely understand the behavior:
          The FORM was not handling the submit event, leaving it to the whim of the
          browser to have its way with the event. Although it sometime ended up
          having two threads serving the request, it didn't always.
          The solution was to put an onSubmit=="return false;" in the <form>
          Hope this helps someone else.
          Jim
          "Jim Gish" <[email protected]> wrote in message
          news:[email protected]...
          > I'm having a strange problem using JSPs whereby a single method call to a
          > bean results in 2 execute threads being created each executing the method
          > called.
          >
          > I have a bean reference in the jsp that has session scope declared like
          this
          > (package names left off):
          >
          > <jsp:useBean id="deployment" class="Deployment" scope="session">
          > <% deployment.init(application); %>
          > </jsp:useBean>
          >
          > I've also set the isThreadSafe value to "false" (since I'm trying to
          > prevent/figure out what's going on):
          > <%@ page isThreadSafe="false" %>
          >
          > Within the JSP body I have code that makes the method call on the
          deployment
          > bean:
          > if (action.equals("Send"))
          > {
          > int status = deployment.send();
          > }
          >
          > Then, within my form I have:
          > <INPUT TYPE="image" SRC="../images/Deploy.gif"
          > onClick="confirmAndSubmit('Send',
          > 'Deploying Application to server <%=
          > deployment.getServer() %>')"/>
          >
          > Where the functions called are:
          > function setActionSubmit(action) {
          > document.deployForm.actionPerformed.value = action;
          > document.deployForm.submit();
          > }
          >
          > function confirmAndSubmit(action, promptString) {
          > if (confirm(promptString)) {
          > setActionSubmit(action);
          > }
          > }
          >
          > Tracing, thread dumping, et al, have confirmed that although I have a
          single
          > session, I end up with two threads each executing the deployment.send()
          > method.
          >
          > Any ideas? I'm stumped.
          >
          > Thanks,
          > Jim
          >
          >
          >
          >
          >