Describe about Applet Security?

The possibility of surfing the Net, wandering across a random page, playing an applet and catching a virus is a fear in which has scared several uninformed people away from Java. This fear has also driven a lot of the establishment of Java in the direction it's gone. Earlier I discussed several security features of Java involving automatic garbage collection, the elimination of pointer arithmetic and the Java interpreter. These serve the dual reasons of making the language easy for programmers and secure for users. You can surf the web without worrying that a Java applet will format your hard disk or introduce a virus within your system.

In fact both Java applets and applications are much safer in practice than code written within traditional languages. This is since even code from trusted sources is likely to have bugs. Therefore Java programs are much less susceptible to common bugs including memory access than are programs written in traditional languages like C. However the Java runtime environment gives a fairly robust means of trapping bugs before they bring down your system. Most users have many more problems along with bugs than they do with deliberately malicious code. Although users of Java applications aren't protected from out and out malicious code, they are largely protected from programmer errors.

Applets implement additional security restrictions in which protect users from malicious code too. This is accomplished by the java.lang.SecurityManager class. This class is subclassed to gives different security environments within different virtual machines. Regrettably implementing this additional level of protection does somewhat restrict the actions an applet can perform. Let's explore precisely what an applet can and cannot do.