As mechanism standard of recovery of classrooms, the Runtime
system loads the classrooms that are stored in local archives, being
able to recoup them at any time, without the necessity to pass for the
ClassLoader. However, some classrooms can not be stored in the system
of local archives, and yes in other machines spread for a net. In
this in case that, the Runtime system calls a subclass the ClassLoader
to load the remote classroom. Loaded classrooms saw net are carried
as a sequence from characters. The ClassLoader then is used to say to
the Runtime system to convert the sequence of characters into an
instance of the Class classroom. The conversion of information is
made by the Runtime system using the method defineClass and the
classrooms that are created by this method can referenciar other
classrooms through its names. To decide these names, the Runtime
system calls the ClassLoader that originally created the classroom.
Manager of Security: The Manager of Security tries to around
strengthen the borders of the Sandbox. When a Java Applet tries to
execute an action that could corrupt or have access information of the
local machine, the Virtual Machine first asks to the Manager of
Security if the action can be executed com.seguran1ca. If the
requested action will be refused by the Manager of Security, will be
shown an error of execution.
2.2 Javascript
Many users of the Internet are surpresos when knowing that
Javascript did not derive from the Java language, that is, the
similarity between them if of the one in the name and for the fact to
be used programming languages to develop executable contents that will
be received by Browsers WWW through the Internet. Javascript was
developed by the Netscape to allow that a programming code could
inside be included of documents HTML. This code can dinamicamente
modify the HTML that will be interpreted, being based on the
conditions of execution of the Browser WWW that received document
HTML. For example, a code segment Javascript can modify the way with
that a Browser will go to show the information in the screen of the
computer being based on the values of the Cookies that they are stored
in the memory of the machine.
One of the functionalities most used of the JavaScript
language is the ability to define events being based on the reactions
of the user. These reactions can be varied possible, as for example,
the positioning of mouse in one determined point of the screen of the
computer can set in motion the small execution of a piece of
JavaScript code. But the characteristics of the JavaScript language
do not only stop in this, it are a complete language, with
mathematical functions, ordinance algorithms and the possibility to
open boxes of dialogue so that the user can interact in its execution
and actions can be executed being based on the replies.
JavaScript does not have the same to be able nor functions to
affect resources of the system as the Java language, however
JavaScript has been used to create the same problems of security that
are created with the Java language.
2.3 ActiveX
Basically, the ActiveX platform is a readjustment of
technologies of the Microsoft for the WWW. The ActiveX standard is
based on the standards of development for Windows known as OLE (Object
Linking and Embedding) and WITH (Component Object Model).
2.3.1 OLE (Object Linking and Embedding) and WITH (Component
Object Model)
WITH it is the object model in which had been constructed
platforms ActiveX and OLE. WITH it allows that an object displays its
functionalities for other components and applications. It defines
mainly as the object will be displayed and as this exposition will
function through the processes and the nets of computers, also
defining as it will be the cycle of life of each Object.
OLE is a tool that allows the desenvolvedores to create
sophisticated applications that operate through multiple platforms.
With the OLE complex documents they can be constructed, that is, a
document can contain some objects of different formats, as for
example, one appears, an electronic spread sheet and a piece of a text
of another document. These objects can be inlaid in the document or
simply on it, that is, in the document alone goes to have a linking
indicating where the object is located. If the initial document that
contains the object will be modified, the document that contains the
linkings for it also automatically will be modified.
2.3.2 ActiveX Controls
The ActiveX controls allow that a programmer creates a reutiliz3avel object of high level with some generic behavior. The programmer can, then, pass the control (or sell it) for one another desenvolvedor, that can use it as a block of construction inside of any tool of programming that has accepted the ActiveX controls. The majority of the main Windows tools such as, C/C++, beginner's all-purpose symbolic instruction code, Paschal and many other languages are compatible with the ActiveX controls. A ActiveX control could be any thing, since a button until a full electronic spread sheet of resources. Thousands of ActiveX controls are available commercially from a variety of manufacturers. The wealth and the abrang4encia of these controls represent the potential greater of the tool.