Let's learn Java. Where are all the java applets?

Hello, beloved reader.
Today you will learn how to sign a JAVA applet. To begin with, I will say that JAVA applets have limited functionality until they are signed. For example, unsigned applets cannot:

• interact with local file system client;
• establish network connections with other servers;
• interact with the client's clipboard;
• some others.

There are several options to solve the problem:
1. Allow execution on each local machine clients. To do this, you can edit the java.policy file, which is located in the folder where the JRE is installed (by default in C:\Program Files\Java\jre6\lib\security). And add necessary permissions. For example, to allow everything that is possible, you need to insert the line:

Grant ( ... permission java.security.AllPermission; )

And if you only need to allow work with the clipboard for the website hackmeplease.com:

Grant codeBase "http://hackmeplease.com/*" ( permission java.awt.AWTPermission "accessClipboard"; );

This method will be convenient only if the number of end users of your site is limited and you can’t afford to edit this file on every computer. In addition, the security of this solution is not very high.

2. Sign your Java applet. So, what do we have as input:
- installed JDK and JRE;
- jar file of your applet (there are some writing peculiarities source code, see below);
- desire to work with the clipboard. To do this, you need the line to work correctly:

Toolkit toolkit = Toolkit.getDefaultToolkit();
Clipboard clipboard = toolkit.getSystemClipboard();

If we call these lines, we will get the following exception from an unsigned applet:
java.security.AccessControlException: access denied (java.awt.AWTPermission accessClipboard)

So let's get started:
0. Go to the BIN folder of our JDK (for example, C:\Program Files\Java\jdk1.6.0_23\bin).
I. Create a local storage of our certificate (keystore):
keytool -genkey -keystore .keystore -alias "Terrasoft" -validity 99999

99999 - period of validity of the certificate in months;
.keystore - file name of the created storage.

If the command is launched successfully, the system will ask us for the password of our storage, as well as some information about the certificate (your full name, company name, city, country and blood type)

As a result, we will have a .keystore file. This is our repository, which we will use to sign various applets.
II. We copy our JAR file to the BIN folder of our JDK. We sign it using the following command:
jarsigner.exe -keystore .keystore ClipboardLibrary.jar "Terrasoft"
where Terrasoft is the name of the alias of our certificate;
.keystore - storage file name;
ClipboardLibrary.jar is the name of the JAR file.
The system will ask us for a password - enter the one you entered in step I.

It seems like it’s ready... Right now, naive...
So, when running a page with our applet on board, the user will receive a friendly message like:

Which means, “User, click Yes and say goodbye to your system, because we can do whatever we want with it.”
By the way, pay attention to NOT VERIFIED. Means that we do not have a trusted certificate. To get a trust, you need to contact special services on the Internet and even pay money.

But let's get back to our sheep. When accessing the clipboard, we will again receive an exception of the form:
java.security.AccessControlException: access denied (java.awt.AWTPermission accessClipboard)

It's a pity. Well, if it didn’t work out now, it will work out another time. Goodbye.

Kidding. In fact, all the applet signing guides I've seen stop at this point. Like, nothing is scary for a signed applet. Let them all be ashamed.
In short, the following trick to make our access to the clipboard work:

III. Change source code.
Instead of calling like:
clipboard = toolkit.getSystemClipboard()
you need to write a call like:
clipboard = (Clipboard) AccessController.doPrivileged(new PrivilegedAction() ( public Object run() ( return toolkit.getSystemClipboard(); ) ));
After this, you need to recompile your JAR and repeat step II (respect to those who read my message from the end).

That's basically all. Should work. I hope that this will be useful to someone, and he will not waste as much of his life on this nonsense as I did. Let problems and scoundrels not bother you in life, just wait (C). See you again on air.

Download and install java applet

To install and subsequently configure the CryptoPro Bank-Client Online system, you will need to download the java applet for VTB 24. You can download it for free on the page http://www.java.com/ru/. This component will be needed if you use browsers such as Mozilla Firefox, Opera, Internet Explorer. But these are not the only browsers that this system supports.

Installing a java applet takes place in two stages:

1. This is the installation of the java SE Runtime Environment platform itself;
2. installing a java applet.

If java is on your personal computer, you should skip the first step. By the way, the PC will not ask you to install this component. Installation takes place in five steps:

1. click “Download” script;
2. click “Agree and start downloading”: a file with the extension .exe for operating system Windows;
3. then you should “Save” the resulting file and run it (by double-clicking with the left mouse button);
4. click the “Install” button;
5. After the installation process is completed, you just have to click on the “Close” button. This will indicate that the installation is complete.

Setting up the script

Configuration is carried out through “Start” in the “Control Panel”. Then open the control panel. All you have to do is disable the protocols: TLS 1.1 and TLS 1.2. This is easy to do: uncheck them. Similarly, disable “Use SSL 2.0 compatible ClientHello format”. All is ready.

Applets

The first two examples presented in this book are applications written in Java language, i.e. independent programs similar to ordinary machine-dependent programs.
On the other hand, as mentioned in the previous chapter, much of the excitement around the Java language was due to its ability to run applets under Web browsers.

We want to show you how to create and run an applet in command line mode.

We will then load this applet into the appletviewer included with the JDK.
Finally, we will display it in the Web browser.

Go to the CoreJavaBook/vlch2/WelcomeApplet directory and then enter
following commands.
javac WelcomeApplet. java
appletviewer WelcomeApplet.html

In Fig. Figure 2.12 shows what you will see in the applet viewer window.

Rice. 2.12. View of the WelcomeApplet applet in the Applet Viewer window

The first command is already familiar to us - it calls the Java language compiler. It compiles the applet source contained in the WelcomeApplet. java by creating the WelcomeApplet bytecode file. class.

However, this time we are not running the Java language interpreter. Instead, we call the appletviewer program. This program is specifically designed for quickly testing applets and is included in java package SDK. It works not with a class file, but with a file in HTML format. The contents of the WelcomeApplet.html file are shown in Listing 2.3.

Listing 2.3
WelcomeApplet.java file

---

This applet is from the book

Core Java by Cay Horstmann and
Gary Cornell, published by Sun Microsystems Press.

---

The source.

If you know HTML, you'll notice some standard HTML commands and an applet descriptor that tells the applet viewer to load the applet code contained in the WelcomeApplet, class file. appletviewer ignores all HTML language descriptors except the applet descriptor.

Other HTML language descriptors are recognized when the HTML file is viewed in a browser that supports languages ​​up to Java 2. There is a problem, however.

Browser versions Netscape 6, Mozilla and Opera browsers support Java 2 language in both Windows environment, so on the Linux platform, although this feature is optional. To experiment with applets, simply download the latest version and make sure it supports Java.

Some versions of Internet Explorer do not support Java at all. Other versions only support very old virtual Java machine Microsoft (Java Virtual Machine). If you are using the Internet Explorer browser running the Windows operating system, go to http://java. sun. com/get Java and download the Java Plug-In program. It will add to the Internet browser Explorer features Java 2.

On the Macintosh platform running the OS X operating system, Java language capabilities are already integrated into the Internet Explorer browser. In particular, at the time of writing this browser supported work with the J2SE package version 1.3. OS 9 only supports the outdated version 1.1.

If you are using the Netscape 4 browser, you can take advantage of the Java 2 language support provided by Java program Plug-In. However, when working with applets loaded using the applet handle, the browser will still use a legacy Java virtual machine. Consequently, you will have to rewrite the HTML file and use the rather inconvenient embed descriptor instead of the applet descriptor. This approach cannot be called satisfactory.

If your browser supports the Java 2 platform, try loading the applet into it. To do this, follow these steps:

Launch your browser.

Select the File -> Open File (or equivalent) option from the menu.
Go to the CoreJavaBook/vlch2/WelcomeApplet directory.

You should see the WelcomeApplet.html and WelcomeAppletPlugin.html files in the dialog box.
Upload the file that matches your setup. The browser will download the applet along with the surrounding text. It will look something like the one shown in Fig. 2.13.

It's easy to see that this application is truly interactive and interacts with the Internet. Click on the "Cay Horstmann" button. The applet will force the browser to open Kay Horstmann's Web page. Click on the "Gary Cornell" button. The applet will open an email window that already contains Gary Cornell's email address.

Fig, 2.13. Launching the WelcomeApplet Applet Using a Browser

Note that none of these buttons work with the Applet Viewer. This program cannot send mail or display a Web page on the screen, so it will simply ignore your requests. The Applet Viewer is good for testing isolated applets, but to actually interact with the Internet and other programs, you must load your applet into a browser.

The applet can be launched from your text editor or integrated development environment. When working with the Emacs editor, select the JDE -> Run Applet option from the menu.

When working with the TextPad editor, select the Tools -> Run Java Applet option or use the keyboard shortcut . A dialog box will open in front of you, in which all HTML files stored in the current directory will be presented. If you press a key , the TextPad editor will automatically create a minimal HTML file.

In Sun ONE Studio, you simply load the HTML file containing the applet descriptors. This environment contains a small browser that executes the applet on the corresponding Web page. Alternatively, you can click right click mouse over the file with the applet source text and set the value of the "Executor" property on the tab to
"Applet Execution".

The Welcome applet code is shown in Listing 2.4. IN this moment it just needs to be skimmed. We'll return to creating applets in Chapter 10.

Import javax.swing.*;
import java.awt.*;
import java.awt.event.*,
import java.net.*;

public class WelcomeApplet extends JApplet
{
public void init()
{
Container contentPane = getContentPane();
contentPane.setLayout(new BorderLayout());

JLabel label = new JLabel(getParameter("greeting") ,
SwingConstants.CENTER);
label.setFont(new Font("Serif", Font.BOLD, 18));
contentPane.add(label, BorderLayout.CENTER);

JPanel panel = new JPanel();

JButton cayButton = new JButton("Cay Horstmann");
cayButton.addActionListener(makeURLActionListener
("http://www.horstmann.com"));
Jbutton garyButton = new Jbutton("Gary Cornell");
garyButton.addActionListener(makeURLActionListener
("mailto:garyOthecornells.com"));
panel.add(garyButton);
contentPane.add(panel, BorderLayout.South);
}
public ActionListener makeURLActionListener(fina1 string u)
{
return new
ActionListener()
{
public void actionPerformed(ActionEvent event)
{
try (
getAppleContext().showDocument(u);
}
catch(Exception e) (e.printStackTrace (); )
{
e. printStackTrace();
}
}
} ;

In this chapter, we studied the mechanisms for compiling and running programs written in the Java language. Now we are ready to move on to Chapter 3, where we will begin learning the Java language.

Following the rapid development of information, VTB, like many other banks, began to introduce a function called “remote banking services" For this purpose, VTB specialists created a special applet - a program through which clients gain access to their accounts. Most often, as in this case, the Java programming language (pronounced “java” or “java”) is used for these purposes. To start using the program from VTB, you need to download the program, install and configure it.

What is a Java Applet for?

This applet works based on three pillars. Their names are: Reliability, Performance and Security. So it is not surprising that applets on this platform are used not only by financial organizations like VTB, but also by accounting departments, scientific enterprises, as well as manufacturers of technical products for household and commercial needs. The platform's capabilities are multifaceted:

• an easy way to create and configure a network application;
• accessibility to work with databases;
• detailed study of unique scenarios for the development of events;
• ability to select filter parameters on input and output;
• access to Internet services;
• automatic memory management;
• full-fledged work with forums, online stores, questionnaires, games and applications on the Internet;
• several programs are executed simultaneously in any of the specified languages;
• support for multi-threaded applications;
• possible messages and errors if it is not loaded;
• various classes for making HTTP requests and processing responses.

The described advantages make the Java platform ideal for the VTB applet.

Possible mistakes

Below are the most common errors that VTB clients encounter after installing the applet, and how to resolve them.

Applet does not launch after updating to Java 7 Update 65

This problem most often affects owners of Windows 7, 8 and 10, with versions of Java 7.0 or 8.0. The essence of the problem boils down to the fact that the VTB applet has stopped running. The reason lies in the absence of the deployment.javaws.jre.0.args= line in the document named deployment.properties. The developers have fixed the problems in Java 7 Update 67 (7u67), so for most, the solution to the problem is to install the latest version of the software. You can download the program from the link: https://www.java.com/ru/download/. The main page looks like this:

In cases where updating is not possible, there are other options. End users version 7u65 it is worth changing the Java Control Panel settings a little. You can do this as follows:

1. “Start” Windows => “Programs”.
2. In the menu that opens, find a list of programs from the manufacturer.
3. Click “Configure Java” to launch the Java Control Panel.
4. After launch, go to the tab with the appropriate name.
5. Click "View".
6. Double click on "Runtime parameters". This will open edit mode.
7. “OK” “Apply”.
8. Last click on “OK” to close the panel.

By following this guide, anyone can set up their VTB applet quite quickly.

You can temporarily solve the problem by amending the code:

1. Removing java_arguments from the applet tag will resolve the issue on the server side.
2. Adding the line deployment.javaws.jre.0.args= to deployment.properties will resolve the issue on the computer side.

This way you will make the VTB applet work and the problem with the update will be solved.

VTB applet is not loaded

An important backstory: of the many technologies that companies used, some were hopelessly outdated and no longer able to perform their functions as intended. However, the owners of large enterprises really regret spending tens/hundreds of thousands of dollars on the development of corporate applications based on the mentioned technologies. In this regard, some clients, when logging into the service, may see an error with the above name.

This also applies to some VTB clients: when trying to log into the remote account management system, the described applet error is displayed. The reason may be that the applet is missing or is not working. However, this is easy to deal with, just follow the simple instructions below.

The easiest way to start is to install the VTB applet from the official Java website. It is worth doing this even when software you already have it, but not enabled: it will be better if you have the most installed on your computer current version programs. So, follow the directions:

1. Go to official page companies on the Internet (the link to the service is located just above in this article).
2. After this, the resource independently determines the parameters of your OS and offers you a link to the appropriate software option.
3. Click "Download Java for Free".
4. Once the download process is complete, run the file and install it following the instructions.
5. Restart your browser.

Important information: starting from version 42 Google Chrome does not officially support Java-based applets, including the VTB applet.

However, it is available in any other browser, for example, Mozilla Firefox. You can enable the applet there as follows:

1. Launch your browser (if it is not installed, download it from https://www.mozilla.org/ru/firefox/new/ and install it according to the instructions).
2. In the application menu, click “Add-ons” =› “Plugins”.
3. Switch the "Java Platform Module" to "Always Enabled" (don't change anything if it's already enabled).
4. Restart your browser.

After these simple manipulations, you can freely access the VTB service: the applet should work without interruptions.

Installing the VTB applet

To install and configure the VTB applet, download it from the link http://www.java.com⁄ru⁄. The applet is suitable for the functionality of such browsers as FireFox, Opera, Internet Explorer (the version of which must be constantly updated).

The applet for working with VTB is installed in two stages:

• installation and configuration of the SE Runtime Environment platform;
• installation of the applet itself.

If you plan to use a personal computer for access, you do not need the first step. The installation procedure consists of five points:

1. "Download".
2. “Agree and start downloading” (file for Windows, extension .exe).
3. “Save” =› launch double click left mouse button.
4. "Install"
5. "Close" after installation is complete.

Then the script needs to be configured:

“Start” =› control panel =› uncheck the TLS 1.1, TLS 1.2 and “Use SSL 2.0 compatible ClientHello format” protocols. Now you have free access to the VTB applet.

Browser settings

Warning window with the message “Attention. Java applet not loaded" may occur due to browsers. To configure them to interact with the VTB applet, follow the instructions in the table below.

Browser	Briefing
Firefox	1. Click on the icon.
	2. In the drop-down menu, select the “Allow and remember” status.
	3. Click OK.
	4. Go to your browser settings.
	5. Select “Add-ons”, sub-item “Plugins”.
	6. Set the status “Enable on request” for all Java sub-items.
Opera	1. Open your browser settings.
	2. In the “Plugins (recommended)” item, select “Run all plugin contents”.
Safari	1. On the registration page in the VTB system, select the menu “Safari” => “Settings” => “Security” => “Customize website”.
	2. Select “Java” in the left list of the dialog. In the right list for the VTB website, set the mode to “On”.
	3. Press and hold ALT while moving the mouse cursor to ON. Then click the mouse button. A drop-down menu will appear, from which you select “Run in safe mode».
	4. Click "Done" and restart your browser.
Internet Explorer	1. In the browser settings, select “Tools” => “Internet Options” => “Advanced”. Uncheck SSL 2.0 and disable the use of TLS 1.1 and 1.2 protocols.
	2. In your browser settings, select “Customize add-ons.”
	3. In the window that appears, select “Run without permission.”
	4. In the list of add-ons, find “Java Plug-in”. The state of this add-on should be Enabled.

So, the VTB applet is a very useful thing, so it is important to know how to correctly install the software for it. For those who like visual demonstrations, watch the video.