eclipse dynamic web project - default start page

1) How can I change the default page ?

=> change welcome file list in web.xml. Change to your desired filename whichever you are using.

2) can I put in default page asp file ?

=> you can change extension to asp, but you need servlet mapping in web.xml. But if you are talking about Microsoft ASP pages, I think you won't be able to add them as per my knowledge as both(jsp and asp) resides under different technologies

EDIT :

<?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" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>MyFirstServlet</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
    <description>new</description>
    <display-name>GrettingServlet</display-name>
    <servlet-name>GrettingServlet</servlet-name>
    <servlet-class>GrettingServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>GrettingServlet</servlet-name>
    <url-pattern>/greetings.asp</url-pattern>
  </servlet-mapping>
</web-app>

Here you will make request to GreetingServlet using url http://localhost:8080/myapp/greetings.asp

In web.xml (under TOMCAT_HOME/webapps/you_application) you have this:

<welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
    <welcome-file>/axis2-web/index.jsp</welcome-file>
  </welcome-file-list>

change to your new file name

Few things to check.

1) Servlet mapping extension in web.xml
2) Welcome file definition in web.xml

Make sure there extension & name are as you changed.

web.xml will be inside WEB-INF folder.