PrimeFaces clicking update button makes file disappear - jsf-2

Question

I'm developing an application in JSF 2.0 and also using the Primefaces component library. But, I'm facing problem with p:fileUpload component of the Primefaces Library. I'm basically trying to achieve the following things.
The user uploads the .xls file and after hitting on Upload button
the file should get saved to a temporary location in the disk.
Next, when the submit button is clicked the saved file would be read
line-by-line using Apache POI and saved to the database.
However, the file disappears once the Upload button button is clicked. Being new in JSF/Primefaces, I couldn't exactly figure out where I'm heading towards?
The worst part is no error message is received and I can see that all the phases of JSF-lifecycle is getting executed. Any help would be much appreciated !!! Below is my code
index.html
<h:body>
<h:form prependId="false" enctype="multipart/form-data" id="welcomeForm" style="width:800px">
<h4 style="color:red; font-family:Arial"><h:outputLabel value="Upload your file:" /></h4>
<p:growl id="growl" showDetail="true" />
<p:fileUpload fileUploadListener="#{fileUploadBean.handleFileUpload}"
mode="advanced"
dragDropSupport="false"
sizeLimit="100000" fileLimit="3"
allowTypes="/(\.|\/)(xls|xlsx|docx|doc)$/"
update="growl"
/>
<p:separator/>
<p:commandButton value="Submit" actionListener="#{fileUploadBean.growlMessage}" update="growl" />
<h:message for="welcomeForm" />
</h:form>
FileUploadBean.java
public class FileUploadBean implements Serializable {
private static final long serialVersionUID = 1L;
private String message;
private UploadedFile uploadedFile;
private String myFileName;
public FileUploadBean(){
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public UploadedFile getUploadedFile() {
return uploadedFile;
}
public void setUploadedFile(UploadedFile uploadedFile) {
this.uploadedFile = uploadedFile;
}
public void growlMessage(){
FacesContext context = FacesContext.getCurrentInstance();
context.addMessage(null, new FacesMessage("Your " + myFileName +"was uploaded successfully") ); }
public void handleFileUpload(FileUploadEvent event) throws IOException {
System.out.println("Reached here:::::");
String name = uploadedFile.getFileName();
System.out.println("File name: " + name);
String type = uploadedFile.getContentType();
System.out.println("File type: " + type);
long size = uploadedFile.getSize();
System.out.println("File size: " + size);
Path folder = Paths.get("C:/Windows/Temp");
String filename = FilenameUtils.getBaseName(uploadedFile.getFileName());
String extension = FilenameUtils.getExtension(uploadedFile.getFileName());
Path file = Files.createTempFile(folder, filename + "-", "." + extension);
try (InputStream input = uploadedFile.getInputstream()) {
Files.copy(input, file, StandardCopyOption.REPLACE_EXISTING);
}
System.out.println("Uploaded file successfully saved in " + file);
FacesMessage msg = new FacesMessage("Succesful", event.getFile()
.getFileName() + " is uploaded.");
FacesContext.getCurrentInstance().addMessage(null, msg);
System.out.println("last line of file upload....");
}
public String save() throws IOException {
System.out.println("Uploaded file value ::::"+uploadedFile);
if(uploadedFile != null) {
FacesMessage message = new FacesMessage("Succesful", uploadedFile.getFileName() + " is uploaded.");
FacesContext.getCurrentInstance().addMessage(null, message);
}
else{
/*String filename = FilenameUtils.getName(e.getFile().getFileName());
System.out.println("Filename is :::: " +filename);*/
System.out.println("Uploaded File Name Is :: "+uploadedFile.getFileName()+" :: Uploaded File Size :: "+uploadedFile.getSize());
System.out.println("FAILED !!!!! FAILED !!!!! FAILED !!!!!");
}
return "true";
}
web.xml file
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">
<display-name>file_uploading</display-name>
<servlet>
<servlet-name>Faces Servlet</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>/faces/*</url-pattern>
</servlet-mapping>
<context-param>
<description>State saving method: 'client' or 'server' (=default). See JSF Specification 2.5.2</description>
<param-name>javax.faces.STATE_SAVING_METHOD</param-name>
<param-value>client</param-value>
</context-param>
<context-param>
<param-name>javax.servlet.jsp.jstl.fmt.localizationContext</param-name>
<param-value>resources.application</param-value>
</context-param>
<context-param>
<param-name>javax.faces.PROJECT_STAGE</param-name>
<param-value>Development</param-value>
</context-param>
<context-param>
<param-name>primefaces.UPLOADER</param-name>
<param-value>auto|native|commons</param-value>
</context-param>
<filter>
<filter-name>PrimeFaces FileUpload Filter</filter-name>
<filter-class>org.primefaces.webapp.filter.FileUploadFilter</filter-class>
<init-param>
<param-name>thresholdSize</param-name>
<param-value>51200</param-value>
</init-param>
<init-param>
<param-name>uploadDirectory</param-name>
<param-value>C:\Windows\Temp</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>PrimeFaces FileUpload Filter</filter-name>
<servlet-name>Faces Servlet</servlet-name>
<dispatcher>REQUEST</dispatcher>
<dispatcher>FORWARD</dispatcher>
</filter-mapping>
<listener>
<listener-class>com.sun.faces.config.ConfigureListener</listener-class>
</listener>
</web-app>