call a method java from a jsp page in liferay ActionRequest

Hi,i have a problem in a jsp. I need to call a method java from a button insert into a jsp page. I can't use the submit button but i need to use "button" type. i have use this code and i have success access into a java method but the java method don't response nothing! i dont know why i see from log that i can access to java class but in case of success the alert into jsp page, return me "undefined" value. N.B. In java i need to use ActionRequest and ActionResponse or a string method java. I can't use doView RenderRequest. I have use in java [login to view URL] but the Success Ajax can't read this? I think that in case of success i need to return a jsonObject? why dont return me nothing? thanks JSP: ______________________________________________________________ <portlet:actionURL var="valideteProcessoActionURL" windowState="normal" name="validateProcesso"></portlet:actionURL> <form id=insertform action="<%=valideteProcessoActionURL%>" name="rispostaForm" method="POST" enctype="multipart/form-data" > <div class="span8"><input type="button" value="VALIDAZ" id="validaProc" onclick="valida()"></div> </form> <aui:script> function valida(){ var upProc = [login to view URL]("uploadProcesso").value; AUI().use('aui-io-request', function(A){ [login to view URL]('<%=[login to view URL]()%>', { method: 'post', <!-- dataType: 'json', --> data: { uploadProcesso: upProc + "aaa"}, on: { success: function(test) { alert(test); var data = [login to view URL]('responseData'); alert("risultato: " + <%= [login to view URL]("risultatoValidaz") %> + <%=risultatoValidaz %> + <%=risultatoValidaz %> + data); <%-- alert("nome: " + <%=[login to view URL]("name")%> + "Rapp: " +<%=[login to view URL]("rapportino")%>); --%> alert([login to view URL]('responseData').jsonObject); [login to view URL]("validazioneProcesso").value = [login to view URL]('responseData').jsonObject; } } }); }); } </aui:script> JAVA: _________________________________________________________________ public JsonObject validateProcesso(ActionRequest request, ActionResponse response) throws IOException, PortletException { UploadRequest uploadRequest = PortalUtil .getUploadPortletRequest(request); String tabs1 = [login to view URL](uploadRequest, "nomeTab"); String uploadProcesso = [login to view URL](uploadRequest, "uploadProcesso"); [login to view URL]("Ciaoooo"); // i see this in log correctly [login to view URL]("uploadProcesso: " + uploadProcesso); // i see this in log correctly and this parameter come from jsp String name = "test"; JsonObject jsonObject = new JsonObject(); [login to view URL]("validazioneProcesso", name + uploadProcesso); [login to view URL]("risultatoValidaz",name); [login to view URL]("risultatoValidaz",name); [login to view URL]("tabs1", tabs1); [login to view URL]("mvcPath", "/html/cat/[login to view URL]"); return jsonObject; }