JavaWebStart-NullPointerException_Java_Nullpointerexception_Java Web Start

JavaWebStart-NullPointerException

java

JavaWebStart-NullPointerException,java,nullpointerexception,java-web-start,Java,Nullpointerexception,Java Web Start,我试图通过使用不带代码库的示例重现简单的JavaWebStart演示，我得到了一个NullPointerException </resources> <application-desc name="Dynamic Tree Demo Application" main-class="webstartComponentArch.DynamicTreeApplication"> </application-d

我试图通过使用不带代码库的示例重现简单的JavaWebStart演示，我得到了一个NullPointerException

    </resources>
    <application-desc
         name="Dynamic Tree Demo Application"
         main-class="webstartComponentArch.DynamicTreeApplication">
     </application-desc>
     <update check="background"/>
</jnlp>

位于的java.lang.NullPointerException com.sun.javaws.Main.launchApp（未知源代码）位于 com.sun.javaws.Main.continueInSecureThread（未知源）位于 com.sun.javaws.Main.access$000（未知来源）位于 com.sun.javaws.Main$1.run（未知源代码）位于 java.lang.Thread.run（未知源）

    </resources>
    <application-desc
         name="Dynamic Tree Demo Application"
         main-class="webstartComponentArch.DynamicTreeApplication">
     </application-desc>
     <update check="background"/>
</jnlp>

我正在逐字使用示例代码。附件是部署文件。

有什么想法吗？

在安德鲁·汤普森的帮助下，我解决了我的问题。首先，我必须使用使用代码库的示例。

    </resources>
    <application-desc
         name="Dynamic Tree Demo Application"
         main-class="webstartComponentArch.DynamicTreeApplication">
     </application-desc>
     <update check="background"/>
</jnlp>

这是我的清单文件：

Permissions: sandbox
**Codebase: localhost:8080/java-web-start**
Application-Name: Dynamic Tree Demo

    </resources>
    <application-desc
         name="Dynamic Tree Demo Application"
         main-class="webstartComponentArch.DynamicTreeApplication">
     </application-desc>
     <update check="background"/>
</jnlp>

这是我的jnlp文件：动态树演示动态团队

    </resources>
    <application-desc
         name="Dynamic Tree Demo Application"
         main-class="webstartComponentArch.DynamicTreeApplication">
     </application-desc>
     <update check="background"/>
</jnlp>

和HTML文件：

    </resources>
    <application-desc
         name="Dynamic Tree Demo Application"
         main-class="webstartComponentArch.DynamicTreeApplication">
     </application-desc>
     <update check="background"/>
</jnlp>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html lang="en-US">
  <head>
    <title>Dynamic Tree Java Web Start Application Page</title>
    <meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
  </head>
  <body>
    <h1>Dynamic Tree Java Web Start Application Demo</h1>

    <script src="https://www.java.com/js/deployJava.js"></script>
    <script>        
        var url = "**http://localhost:8080/java-web-start/dynamictree_webstart.jnlp**";
        deployJava.createWebStartLaunchButton(url, '1.6.0');
    </script>
    <noscript>JavaScript is required for this page.</noscript>

  </body>
</html>


动态树Java Web开始应用程序页面
动态树Java Web Start应用程序演示
变量url=”**http://localhost:8080/java-web start/dynamictree_webstart.jnlp**”；
createWebStartLaunchButton（url“1.6.0”）；
此页面需要JavaScript。

“有什么想法吗？”自编写该教程以来，情况发生了很大变化。它正在进入一个应用程序开发的阶段。除非不仅指定了代码库，而且在主Jar的清单中实际列出了代码库，否则无法进入屏幕。非常感谢。成功了。很高兴你把它整理好了。现在，您可以删除问题或写下（然后接受）答案。我更喜欢第二种选择，因为它可能对其他人有帮助。