gwt getModuleBaseURL on same server creates an java.lang.UnsatisfiedLinkError - gwt

Question

I have a single GWT web-application integrated with Spring MVC. I have a working Controller which works perfectly and is unit tested to accept POSTed JSON data and returns JSON data.
From within the same application, to avoid any SOP cross-site domain issues, I am making a call with a RequestBuilder to POST the same json data, and I expect JSON data back.
I created a basic java class that should make a call, but I have a few issues. This running web-app is running in hosted mode in Jetty in Eclipse. I have done a ton of research on how GWT should make a call to an existing web-service with a simple HTP request.
The first issue from my unit test is that:
String baseUrl = GWT.getModuleBaseURL();
is not working and I get:
java.lang.UnsatisfiedLinkError: com.google.gwt.core.client.impl.Impl.getModuleBaseURL()Ljava/lang/String;
I think I know what the correct URL should be, so when I hard-code the url correctly, and execute this code:
String url = getRootUrl() + "rest/pendingInvoices/searchAndCount";
System.out.println("PendingInvoiceDataSource: getData: url=" + url);
// Send request to server and catch any errors.
RequestBuilder builder = new RequestBuilder(RequestBuilder.POST, url);
builder.setHeader("Accept", "application/json");
builder.setHeader("Content-type", "application/json");
// builder.setRequestData(requestData);
try
{
System.out.println("PendingInvoiceDataSource: SEND REQUEST: getData: requestData=" + requestData);
Request request = builder.sendRequest(requestData, new RequestCallback()
{
public void onError(Request request, Throwable exception)
{
System.out.println("Couldn't retrieve JSON");
}
#Override
public void onResponseReceived(Request request, Response response)
{
if (200 == response.getStatusCode())
{
// updateTable(JsonUtils.safeEval(response.getText()));
System.out.println("data=" + response.getText());
}
else
{
System.out.println("Couldn't retrieve JSON (" + response.getStatusText() + ")");
}
}
});
}
catch (RequestException e)
{
System.out.println("Couldn't retrieve JSON");
}
I get this error on he sendRequest:
java.lang.UnsatisfiedLinkError: com.google.gwt.xhr.client.XMLHttpRequest.create()Lcom/google/gwt/xhr/client/XMLHttpRequest;
at com.google.gwt.xhr.client.XMLHttpRequest.create(Native Method)
at com.google.gwt.http.client.RequestBuilder.doSend(RequestBuilder.java:383)
at com.google.gwt.http.client.RequestBuilder.sendRequest(RequestBuilder.java:261)
I think this might be a quick fix, or maybe something small I have forgotten, so I'll try some more testing and see what I can find.

Answer 1

Everything client in GWT is only meant to run on the client-side: compiled to JS or in DevMode.
Only shared, server and vm classes can be used on the server-side.
If you want to get your server URL, use the appropriate methods from the HttpServletRequest (or whatever it is in Spring MVC as it seems from how you tagged the question that's what you're using).
If you want to make HTTP requests from your server, use an HttpURLConnection, or OkHttp, Apache Http Components or similar libraries, or even Spring's own HTTP client API.

Answer 2

Actually, it was only the Unit Test that was having a problem. Once I actually tried to run the deployed code, it all worked. I'll still try h GWTTestCase as suggested in order to get the unit test working.
But everything worked correctly when I ran the deployed code.
I also changed: String baseUrl = GWT.getModuleBaseURL();
which gave me:
http://localhost:8888/MyProject
To: String baseUrl = GWT.getHostPageBaseURL();
which gave me:
http://localhost:8888/
and that all worked.