Servlets are Java's answer to CGIs. They are programs that run on your web sever, and can dynamically build web pages. Java Servlets are more efficient than CGIs. Each request to a CGI script is answered in a separate process by a separate instance of the CGI script. A servlet doesn't run in a separate process, and stays in memory between requests. Servlets also load in only a single instance, answering all requests at the same time.
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