appletviewer Command in Linux

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Java Development Kit, better known as JDK, is the most frequently used development environment for creating applications that use the Java programming language. The older JDK versions contain a command line utility named appletviewer that is used for testing and debugging Java applets.

In the latest JDK versions, however, this tool is not available because of several reasons, such as security concerns, development complexity, incompatibility with modern web standards, etc.

If you still want to use this command for some specific purpose, you must install an older version of Java JDK (i.e., JDK 8 or earlier).

Table of Contents

Here is a comprehensive guide to the options available with the appletviewer command −

• appletviewer Command in Linux
• Step 1: Install Java JDK
• Step 2: Verify Java Installation
• Step 3: Syntax to Use appletviewer Command in Linux
• Step 4: Using appletviewer Command in Linux
• Step 5: Compile Java Applet Code From the Linux Terminal
• Step 6: Create an HTML File
• Step 7: Run the appletviewer Command
• Key Aspects of AppletViewer Command in Linux

appletviewer Command in Linux

The appletviewer command opens URLs and shows any applets found on those pages in separate windows. It is important to note that if the pages from the URLs do not contain any applets using the <object>, <embed>, or <applet> tags, then the appletviewer command does nothing.

As discussed earlier, the appletviewer command is deprecated for security reasons and is unavailable in the JDK 9 and later versions. To use this command on your Linux operating system, you must have an older version of the JDK installed on your system. To do this, go through the following steps −

Step 1: Install Java JDK

You can install an older version of JDK on your system by executing the below-mentioned command from the Linux terminal −

sudo apt install openjdk-8-jdk openjdk-8-jre -y

Step 2: Verify Java Installation

Execute the below command to confirm that JDK 8 or an earlier version is installed on your system −

java -version

The following output snippet shows that we are using “openjdk 1.8.0_412” on our Linux system −

Step 3: Syntax to Use appletviewer Command on Linux

After the successful installation of Java JDK 8 or an earlier version, you can use the appletviewer command by following the given syntax −

appletviewer <filename>

Replace <filename> with a valid file name that contains the applet you want to execute using the appletviewer command.

Step 4: Using appletviewer Command in Linux

Let’s consider an example of how the appletviewer command works in Linux. For this purpose, first create a file named “exampleClass.java” using the following command −

nano exampleClass.java

Now paste the below-given code into it −

import java.awt.*;
import java.applet.*;

public class exampleClass extends Applet{

   public void init(){   
      setForeground(Color.white);
      setBackground(Color.gray);
   }

   public void appletPaint(Graphics graph){
      graph.drawString("Hi Geeks! Let's Learn appletviewer Command", 30,30);
   }
}

In this code −

• First, we import all the classes of the “java.awt” and “java.applet” packages.
• Next, we create an “exampleClass” that extends the Applet class.
• Within this class, we invoke the init() method that sets the foreground and background color to white and gray, respectively.
• After this, we create a public method “appletPaint()” that displays the text "Hi Geeks! Let's Learn appletviewer Command" at the coordinates (30, 30).

Step 5: Compile Java Applet Code From the Linux Terminal

Now press “CTRL+X” to save this code in a file named “exampleClass.java” and compile it by executing the below-mentioned command −

javac exampleClass.java

The cursor moves to the subsequent line, indicating that the “exampleClass” has been compiled successfully. On successful execution, this command will generate a new file named “exampleClass.class”.

Step 6: Create an HTML File

Now create a file named “exampleClass.html” and paste the following code into it −

<html>
<body>
   <applet code="exampleClass.class" width="350" height="200"></applet>
</body>
</html>

In this HTML code, the applet tag specifies the compiled Java class file (exampleClass.class) to load and execute the applet −

Press “CTRL+X” and then “y” to save the changes to the file; after this hit the “Enter” key to navigate back to the terminal.

Step 7: Run the appletviewer Command

In the terminal, write the appletviewer command followed by the HTML file name to execute the applet code and get the desired results −

appletviewer exampleClass.html

When we execute this command, a new window pops up that shows the following results −

This is how the appletviewer command works in Linux.

Key Aspects of appletviewer Command in Linux

The following table highlights different aspects of the appletviewer command in Linux. These points will help you understand when to use or not use the appletviewer command in Linux −

This sums up the appletviewer command in Linux.

Conclusion

appletviewer is a command-line utility that was used for testing and debugging applets in JDK 8 and earlier versions. However, Oracle deprecated this command due to security and browser-compatibility issues. Do you still want to use it for some specific purposes? Well! You can do that by installing an older JDK version (i.e., JDK 8 or an earlier version). In this write-up, we explained how you can install an older JDK version, verify its installation, and then use the appletviewer command to execute a Java applet.

For better understanding of the appletviewer command, we create a Java file in the nano editor that extends the Applet class. Within this class we specify some code to display a message on the applet. After this, we compile the code using the “javac” command, and specify the compiled code in an HTML file using the <applet> tag. Finally, we execute the appletviewer command to get the desired results.