You should map the form to the action that accept data submitted. Use Struts tags
<%@ taglib prefix="s" uri="/struts-tags" %>
<s:form action="Welcome" ...
<s:textfield name="username" ...
<s:password name="unknown" ...
couldn't map the password field because in your action there's not a property. May be if you create it
private String unknown;
public String getUnknown() {
return unknown;
}
public void setUnknown(String unknown) {
this.unknown = unknown;
}