Servlets beat CGI

The main drawback to CGI is that it must run a new copy of the CGI-aware program
for each request. This is a relatively expensive process that can bog down
high-volume sites where thousands of requests are serviced per minute. Another
drawback is that CGI programs tend to be platform dependent. A CGI program
written for one operating system may not run on another.

Sun’s Java Servlet platform directly addresses the two main drawbacks of CGI programs.
First, servlets offer better performance and utilization of resources than
conventional CGI programs. Second, the write-once, run-anywhere nature of Java
means that servlets are portable between operating systems that have a Java Virtual
Machine (JVM).