jnlp file contains a typo. The <description> tag is imperfect, missing closing '>'.
As a result, the security dialog 'Application Blocked by Java Security' is presented.
This is confusing and misleading, as the application implements the manifest attributes
and is signed with an official certificate.

Here is the imperfect jnlp file:

# more simple-defective.jnlp
<?xml version="1.0" encoding="utf-8"?>
<jnlp codebase = "http://xxx:8880/simpleNoGUI-defective" href="simple-defective.jnlp" >
  <information>
        <title>Java Web Start - Simple</title>
        <vendor>Simple Demo w/o GUI </vendor>
        <descriptionWebStart Simple App</description>
  </information>

  <security>
        <all-permissions/>
  </security>

  <resources>
        <j2se version="1.8+" />
  </resources>
  <resources>
        <jar href="simple.jar" />
  </resources>

  <application-desc main-class="webstart.Simple" >
  </application-desc>

</jnlp>