How do I fix this Error 500 when trying to connect to a web service?

Question

I am trying to connect to a cXML Web Service using Visual Studio 2010 .NET 4, and when I try to Add a Service Reference to the project using the URL I get the following error (i have masked the url for privacy) why am I getting this error and how can I connect to the web service?...

There was an error downloading 'http://00.00.00.00:8080/xml/servlet/twaaserver?svcname=x10h015'
The request failed with the error message:
--
<h1>Error: 500</h1>
<h2>Location: /xml/servlet/twaaserver</h2><b>Internal Servlet Error:</b><br> <pre>javax.servlet.ServletException
    at processService.doProcess(processService.java:447)
    at processService.run(processService.java:585)
    at twaaserver.doGet(twaaserver.java:429)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
    at org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:405)
    at org.apache.tomcat.core.Handler.service(Handler.java:287)
    at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372)
    at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:812)
    at org.apache.tomcat.core.ContextManager.service(ContextManager.java:758)
    at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java:213)
    at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416)
    at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501)
    at java.lang.Thread.run(Thread.java:534)
</pre>
<b>Root cause:</b>
<pre>java.lang.NullPointerException
    at eboservice.transformDataFeeds(eboservice.java:982)
    at processService.doProcess(processService.java:279)
    at processService.run(processService.java:585)
    at twaaserver.doGet(twaaserver.java:429)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
    at org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:405)
    at org.apache.tomcat.core.Handler.service(Handler.java:287)
    at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372)
    at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:812)
    at org.apache.tomcat.core.ContextManager.service(ContextManager.java:758)
    at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java:213)
    at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416)
    at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501)
    at java.lang.Thread.run(Thread.java:534)
</pre>


--.
Metadata contains a reference that cannot be resolved: 'http://00.00.00.00:8080/xml/servlet/twaaserver?svcname=x10h015'.
The content type text/html of the response message does not match the content type of the binding (application/soap+xml; charset=utf-8). If using a custom encoder, be sure that the IsContentTypeSupported method is implemented properly. The first 1024 bytes of the response were: '<h1>Error: 500</h1>
<h2>Location: /xml/servlet/twaaserver</h2><b>Internal Servlet Error:</b><br><pre>javax.servlet.ServletException: Warning: can't output text before document element!  Ignoring...
    at processService.doProcess(processService.java:447)
    at processService.run(processService.java:585)
    at twaaserver.doGet(twaaserver.java:429)
    at twaaserver.doPost(twaaserver.java:535)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
    at org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:405)
    at org.apache.tomcat.core.Handler.service(Handler.java:287)
    at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372)
    at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:812)
    at org.apache.tomcat.core.ContextManager.service(ContextManager.java:758)
    at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java:213)
    at org.apache.tomcat.service.'.
The remote server returned an error: (500) Internal Server Error.
If the service is defined in the current solution, try building the solution and adding the service reference again.

Answer 1

You're right, I figured out the problem was that the web service was not a SOAP service. It is a REST service.

The problem was that I was trying to Add A Service Reference via the Visual Studio tool. This isn't possible with this type of service I was connecting to because it uses cXML and is a REST service (it works very differently).

In my solution I manually wrote Web Service REST calls by doing simple POST and GET requests and passed in the XML in string format.

This worked for me... I used this tutorial: https://developer.yahoo.com/dotnet/howto-rest_cs.html

Answer 2

There seems to be something wrong with your service or how you call it.

The first thing I usally do is verifying if the service works as expected. Get soapUI import the wsdl and do some sample calls.

Sometimes services go crazy if you don't pass the parameters correctly. If it is not working with soapui clarify what is wrong with the service vendor.