{"id":197840,"date":"2024-02-13T05:26:05","date_gmt":"2024-02-13T05:26:05","guid":{"rendered":"https:\/\/www.henryharvin.com\/blog\/?p=197840"},"modified":"2024-12-23T10:34:12","modified_gmt":"2024-12-23T10:34:12","slug":"applet-in-java-fundamentals-you-need-to-know","status":"publish","type":"post","link":"https:\/\/www.henryharvin.com\/blog\/applet-in-java-fundamentals-you-need-to-know\/","title":{"rendered":"Applet In Java: Fundamentals You Need To Know"},"content":{"rendered":"\n

An applet is a Java application incorporated into a webpage. Even though it functions as a front-end, it runs within the web computer. As they operate inside the web browser, they make the page interactive and dynamic. Thus, Applet in Java<\/a> is not a stand-alone program. Also, they are small applications that run within the address bar.<\/span><\/p>\n\n\n\n

Difference Between An Applet and a Standalone Java<\/span><\/h2>\n\n\n\n
\"applets\"<\/figure><\/div>\n\n\n\n

A few differences between an applet and a standalone Java application are as follows: <\/span><\/p>\n\n\n\n

  1. Class Structure: Applet is a Java class that extends java.applet.Applet class.<\/span><\/li>
  2. Invocation: Java uses the main() method, but Applet invokes the start(). <\/span><\/li>
  3. Embedding: Java is a standalone program, while <\/span>HTML page embeds an applet.<\/span><\/li>
  4. Code Download: After you open an HTML page, you download the code for the applet. But in Java, you must download the entire code before compiling.<\/span><\/li>
  5. JVM Requirement: An applet relies on a web browser. On the other hand, Java executes without them.<\/span><\/li>
  6. Security Rules: The applet enforces strict security rules, often called sandbox security. Java is not subject to the same level of browser-enforced security.<\/span><\/li>
  7. Class Distribution:  Applets can download additional classes on runtime. But we must ensure all the necessary classes are available before running in Java.<\/span><\/li><\/ol>\n\n\n\n

    How does Applet in Java work?<\/span><\/h2>\n\n\n\n

    Applets uses the <applet> tag to load into a web page. The browser then downloads the applet’s code and runs it within the JVM. They run within a sandboxed environment for security reasons. Thus restricting their access to the user’s system. <\/span><\/p>\n\n\n\n

    The Life Cycle Of An Applet<\/span><\/h2>\n\n\n\n

    An Applet’s life cycle involves developing, launching, halting, and demolishing an object in an application’s implementation. In short, it has five main methods: paint(), destroy(), stop(), init(), and start(). Firstly, when an applet starts, i<\/span>t calls the following methods in sequence: init( ), start( ) and paint( ). When we destroy an applet, i<\/span>t calls the following <\/span>methods<\/span> in sequence: stop( ) and destroy( ). <\/span><\/p>\n\n\n\n

    \"\"<\/figure><\/div>\n\n\n\n

    1. Init()<\/h3>\n\n\n\n

    When we call the applet in the browser, it executes the init() function. Thus, the initializing<\/span> phase happens. In the entire process, it calls the function only once. The web browser creates the initialized objects. Then, it executes the init() function inside the applet once it confirms the authentication setting.<\/span><\/p>\n\n\n\n

    2. Start()<\/h3>\n\n\n\n

    The start( ) method execute<\/span>s after init( ). Moreover, this function is invoked in order to restart an applet after it stops. The init() is called only when the applet is loaded, but start( ) is accessed each time the HTML document is visible on the screen. So, if a user leaves a web page and returns, the applet resumes execution at the start() method.<\/span><\/p>\n\n\n\n

    3. Stop()<\/h3>\n\n\n\n

    The stop() function ends the execution of an applet. Every time w<\/span>e minimize<\/span>, pause, or switch between tabs, <\/span>the applet triggers the stop() function. <\/span>It calls the start() function again when we return to the same page.<\/span><\/p>\n\n\n\n

    4. Destroy()<\/h3>\n\n\n\n

    When the applet completes its task, the destroy() function terminates it. For instance, when the applet in the tab or window is closed, the destroy() function is triggered. An applet, once deleted, cannot be restarted. Also, the stop() function is always invoked before the destroy() method.  <\/span><\/p>\n\n\n\n

    5. Paint()<\/h3>\n\n\n\n

    The Graphics class contains the paint() function. It draws forms like squares, circles, trapeziums, etc in an applet. I<\/span>t executes this function after a call to the start() function. Also, <\/span>the applet calls the paint( ) method each time <\/span>it has to redraw an output. This situation can occur for several reasons. For instance, w<\/span>hen we minimize and then restore the applet window. Again, w<\/span>e invoke the paint() method a<\/span>nd the start() every time the applet in Java loads on the HTML page. <\/span><\/p>\n\n\n\n

    Types of Applets<\/span><\/h2>\n\n\n\n

    Depending on their storage place and ease of access, applets are classified as local or remote<\/span>.<\/span><\/p>\n\n\n\n

    1. Local Applet<\/span><\/h3>\n\n\n\n

    A local applet is created and stored on the local machine. When an HTML page recognizes a local applet in the Java system’s memory, it gets data from the pathname or folder name. Thus, a local applet defines two properties – the source folder that defines the path name and the code itself that defines the filename containing the applet’s programming.\u00a0<\/span>Top 10 Java Tools That You Should LearnTop 10 Java Tools That You Should Learn<\/p>\n\n\n\n

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