Chapter 9. Security

The last method is the most important. Permissions have an ordering, in which more general permissions imply more specific ones. Consider the file permission

p1 = new FilePermission("/tmp/-", "read, write");

This permission allows reading and writing of any file in the /tmp directory and any of its subdirectories.

This permission implies other, more specific permissions:

p2 = new FilePermission("/tmp/-", "read");
p3 = new FilePermission("/tmp/aFile", "read, write");
p4 = new FilePermission("/tmp/aDirectory/-", "write");

In other words, a file permission p1 implies another file permission p2 if

The target file set of p1 contains the target file set of p2.

The action set of p1 contains the action set of p2.
这是讲的哪出？losting