App Engine <threadsafe> element missing error

Question

So I have this error that i've seen many people have:

appengine-web.xml does not contain a <threadsafe> element.

But the solution always provided is to just add

<threadsafe>true</threadsafe>

to the appengine-web.xml file. This is my appengine-web.xml file:

<?xml version="1.0" encoding="utf-8"?>
<appengine-web-app xmlns="http://appengine.google.com/ns/1.0">
  <application>dummy</application>
  <version>1</version>
  <threadsafe>true</threadsafe>
  <!-- Configure java.util.logging -->
  <system-properties>
    <property name="java.util.logging.config.file" value="WEB-INF/logging.properties"/>
  </system-properties>
</appengine-web-app>

And still I get the error that no threadsafe element is found?

Answer 1

I think <threadsafe>true</threadsafe> needs to be the first entry in your appengine-web.xml

Here is my xml withouth error:

<appengine-web-app xmlns="http://appengine.google.com/ns/1.0">
    <!--<async-session-persistence enabled="true"/>-->
    <threadsafe>true</threadsafe>
    <application>dummy</application>

    <version>443</version>
    <sessions-enabled>true</sessions-enabled>
    <inbound-services>
        <service>mail</service>
        <service>xmpp_message</service>
    </inbound-services>
    <system-properties>
      <property name="com.google.gdata.DisableCookieHandler" value="true"/>
    </system-properties>
</appengine-web-app>