//File: index.jsp
<Html>
<!--
Copyright (c) 1999 The Apache Software Foundation. All rights
reserved.
-->
<%
double freeMem = Runtime.getRuntime().freeMemory();
double totlMem = Runtime.getRuntime().totalMemory();
double percent = freeMem/totlMem;
if (percent < 0.5) {
%>
<jsp:forward page="one.jsp"/>
<% } else { %>
<jsp:forward page="two.html"/>
<% } %>
</html>
//File: one.jsp
<html>
<!--
Copyright (c) 1999 The Apache Software Foundation. All rights
reserved.
-->
<body bgcolor="white">
<font color="red">
VM Memory usage < 50%.
</html>
//File: two.html
<html>
<!--
Copyright (c) 1999 The Apache Software Foundation. All rights
reserved.
-->
<body bgcolor="white">
<font color="red">
VM Memory usage > 50%.
</html>
（出处：http://www.knowsky.com）