ClassLoader: The ClassLoader is defined as being an abstract classroom that can be used to choose the load politics of Java classrooms for the execution environment, thus defining which classrooms can be executed and which cannot.

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.



Próximo