Editing Servlets (section)

===Disadvantages of other Techniques===
CGI is not without drawbacks. Performance and scalability are big problems since a new process is created for each request, quickly draining a busy server of resources. Sharing resources such as database connections between scripts or multiple calls to the same script is far from trivial, leading to repeated execution of expensive operations. 
Security is another big concern. Most Perl scripts use the command shell to execute OS commands with user-supplied data, for instance to send mail, search for information in a file, or just leverage OS commands in general. This use of a shell opens up many opportunities for a creative hacker to make the script remove all files on the server, mail the server's password file to a secret account, or do other bad things that the script writer didn't anticipate. 
The Web server vendors defined APIs to solve some of these problems, notably Microsoft's ISAPI and Netscape's NSAPI. But an application written to these proprietary APIs is married to one particular server vendor. If you need to move the application to a server from another vendor, you have to start from scratch. Another problem with this approach is reliability. The APIs typically support C/C++ code executing in the Web server process. If the application crashes, e.g. due to a bad pointer or division by zero, it brings the Web server down with it. 
Servlets sind wie der Name schon andeutet server-basierte Java-Klassen, deren grundsätzliche funktionsweise mit der von CGI-Programmen vergleichbar ist. Sie laufen auf dem Server und erstellen dort in der Regel dynamische HTML-Seiten, deren Inhalt zum Beispiel aus Datenbankabfragen resultieren kann.