Unsafe Mobile Code: Public finalize() Method

Abstract
The program violates secure coding principles for mobile code by declaring a finalizemethod public.

Description
A program should never call finalize explicitly, except to call super.finalize inside an implementation of finialize. In mobile code situations, the otherwise error prone practice of manual garbage collection can become a security threat if an attacker can maliciously invoke one of your finalize methods because it is declared with public access. If you are using finalize as it was designed, there is no reason to declare finalize with anything other than protected access.

Examples
The following Java Applet code mistakenly declares a public finalize method.

public final class urlTool extends Applet { public void finalize { ...		}		...	}

Mobile code, in this case a Java Applet, is code that is transmitted across a network and executed on a remote machine. Because mobile code developers have little if any control of the environment in which their code will execute, special security concerns become relevant. One of the biggest environmental threats results from the risk that the mobile code will run side-by-side with other, potentially malicious, mobile code. Because all of the popular web browsers execute code from multiple sources together in the same JVM, many of the security guidelines for mobile code are focused on preventing manipulation of your objects' state and behavior by adversaries who have access to the same virtual machine where your program is running.