Java Platform, Enterprise Edition (Java EE) 8
The Java EE Tutorial
Server push is the ability of the server to anticipate what will be needed by the client in advance of the client’s request. It lets the server pre-populate the browser’s cache in advance of the browser asking for the resource to put in the cache.
Server push is the most visible of the improvements in HTTP/2 to appear in the servlet API. All of the new features in HTTP/2, including server push, are aimed at improving the performance of the web browsing experience.
Server push derives its contribution to improved browser performance from the
fact that servers know what additional assets (such as images, stylesheets,
and scripts) go along with initial requests. For example, servers might know
that whenever a browser requests
index.html, it will shortly thereafter
style.css. Servers can preemptively
start sending the bytes of these assets along with the bytes of the
To use server push, obtain a reference to a
PushBuilder from an
edit the builder as desired, then call
push(). See the
javadoc for the class
javax.servlet.http.PushBuilder and the method
To view the GlassFish samples code for this feature, see https://github.com/javaee/glassfish-samples/tree/master/ws/javaee8.