The exception is generated when we try to load a class of package java.*
from a source that is different from the local file system.
The JVM provides java.* classes with particular privilidges.
This is why it is forbidden such a loading operation.
class which handles communication with NetworkClassLoader.
It waits for a class request (the name is a String).
The requested class is searched first in the cache (a byte array cache), and then
in CLASSPATH of the server machine.