Developer's Guide to Web Application Security

We can also extend the SecurityManager class and override the methods to

create our behavior. First, let’s look at what the methods in the SecurityManager do.

There are about 30 methods that all begin with “check,” such as checkWrite(),

checkRead(), and checkConnect(). If a SecurityManager is loaded, whenever one of

the hazardous operations is attempted, a check method will be invoked.The check

methods are invoked by other methods in the Java library. For example, before the

FileOutputStream class actually attempts to write to a file, it would invoke code that

looks like this:

SecurityManager security = System.getSecurityManager();

if (security != null) ...