Cannot use rename-to in RPC

[peter tong]

in the module file, I set

<module rename-to="abc">

and in service, I write the annotation
@RemoteServiceRelativePath("search")

then in web.xml, I write

<servlet-mapping>
...
<url-pattern>/abc/search</url-pattern>

but when I call the service, error thrown,
if in web.xml, I write

<servlet-mapping>
...
<url-pattern>/com.ha.als.ALS/search</url-pattern>
</servlet-mapping>

then the RPC can be successfully called!!
GWT.getModuleBaseURL() return "http://127.0.0.1:8888/com.ha.als.ALS/"
why /abc/search will fail to call the RPC as I already rename the module to "abc" in module file(ALS.gwt.xml)?

To show the debug message, I code onFailure method as follow:

public void onFailure(Throwable caught){
  for (int i=0; i<caught.getStackTrace().lenght;i++){
     System.out.println(caught.getStackTrace()[i];
  }
  System.out.println(caught.getStackTrace());
}

and the output is

[WARN] 404 - POST /com.ha.als.ALS/search (127.0.0.1) 1407 bytes
Request headers
Accept: */*
Accept-Language: en-us
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; InfoPath.2)
Accept-Encoding: gzip, deflate
Host: 127.0.0.1:8888
Connection: Keep-Alive
Referer: http://127.0.0.1:8888/ALS.html?gwt.codesvr=127.0.0.1:9997
x-gwt-module-base: http://127.0.0.1:8888/com.ha.als.ALS/
Content-Type: text/x-gwt-rpc; charset=utf-8
x-gwt-permutation: HostedMode
Content-Length: 269
Cache-Control: no-cache
Response headers
Content-Type: text/html; charset=iso-8859-1
Content-Length: 1407
com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:209)
com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:287)
com.google.gwt.http.client.RequestBuilder$1.onReadyStateChange(RequestBuilder.java:395)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:337)
com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:218)
com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)
com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561)
com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269)
com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
com.google.gwt.core.client.impl.Impl.apply(Impl.java)
com.google.gwt.core.client.impl.Impl.entry0(Impl.java:213)
sun.reflect.GeneratedMethodAccessor34.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:292)
com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:546)
com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:363)
java.lang.Thread.run(Thread.java:662)

Also, even I use

<servlet-mapping>
...
<url-pattern>/com.ha.als.ALS/search</url-pattern>
</servlet-mapping>

there is a warning message in eclipse as follow

[WARN] Server class 'javax.validation.Path' could not be found in the web app, but was found on the system classpath
[WARN] Adding classpath entry 'file:/D:/eclipse/plugins/com.google.gwt.eclipse.sdkbundle_2.4.0.v201201120043-rel-r36/gwt-2.4.0/validation-api-1.0.0.GA.jar' to the web app classpath for this session
For additional info see: file:/D:/eclipse/plugins/com.google.gwt.eclipse.sdkbundle_2.4.0.v201201120043-rel-r36/gwt-2.4.0/doc/helpInfo/webAppClassPath.html
[WARN] Server class 'com.google.gwt.core.client.GWTBridge' could not be found in the web app, but was found on the system classpath
[WARN] Adding classpath entry 'file:/D:/eclipse/plugins/com.google.gwt.eclipse.sdkbundle_2.4.0.v201201120043-rel-r36/gwt-2.4.0/gwt-dev.jar' to the web app classpath for this session
For additional info see: file:/D:/eclipse/plugins/com.google.gwt.eclipse.sdkbundle_2.4.0.v201201120043-rel-r36/gwt-2.4.0/doc/helpInfo/webAppClassPath.html