We Keep Coding

How to put jar file in embed tag in html

i have applet tag that have the following
<applet id="ZFComponent"
codebase="java.code.webcomponents.ZFApplet" archive="ZFApplet.jar" width="0" height="0">
This browser does not support Embed.
</applet>
and i want to use embed tag instated to make it work in Mozilla family of browsers

You have to specify the class that you want do embed from the jar file.
Like this:
<applet id="ZFComponent" ARCHIVE="ZFApplet.jar" CODE="ZFApplet.class" width="0" height="0">
This browser does not support Embed.
</applet>
This is assuming the class you want to embed is ZFApplet.
EDIT: The above code will work on some browsers but it is going extinct because using applet tags introduces a lot of security risks. Chrome no longer supports the applet tag and you should only be running Java in Chrome through Java Web Start (and even with that it prompts the user about running Java.)
See the notice on Oracle's site:
Chrome no longer supports NPAPI (technology required for Java applets)
The Java plug-in for web browsers relies on the cross platform plugin architecture NPAPI, which has been supported by all major web browsers for over a decade. Google's Chrome version 45 (scheduled for release in September 2015) drops support for NPAPI, impacting plugins for Silverlight, Java, Facebook Video and other similar NPAPI based plugins.
Java applications are offered through web browsers as either a web
start application (which do not interact with the browser once they
are launched) or as a Java applet (which might interact with the
browser). This change does not affect Web Start applications, it only
impacts applets.
If you have problems accessing Java applications using Chrome, Oracle
recommends using Internet Explorer (Windows) or Safari (Mac OS X)
instead.
Happy Coding!

How does java run its applets in the browser?

Well, we are long past the days of ActiveX controls running in Internet Explorer so my question is how does java manipulate the browser into displaying the applet on the web page?

how does java manipulate the browser into displaying the applet on the web page?
It doesn't. The user installs an NPAPI (Netscape Plugin API) plugin which tells the browser it can run Java applets. Then, when the browser sees a Java applet, it fires up the plugin.
It's worth noting that Chrome no longer supports the NPAPI on Linux, and they're scheduled to stop supporting it on Windows in September. As far as I know, officially Mozilla calls NPAPI plugins a "legacy" feature and recommends using other options, but is continuing to support them via click-to-play (at least for now)..

Java Applets consists of compiled byte-code, which is executed under
the control of a JVM. Applets may either be untrusted which limits their capabilities or may be trusted which increases their access permissions and allows them to access user data or hardware.
Java applet runs in browser using Java Plug-in technology (hereafter the "Java Plug-in"), which is included in the Java Runtime Environment (JRE), enables Java applets to run in web browsers on the desktop. The Java Plug-in provides powerful capabilities to applets in the web browser. With the Java Plug-in, applets are not run in the JVM inside the browser. Instead, they are executed in a separate process. The same JVM process can be shared between multiple applets, or applets can be placed into different processes depending on whether the existing JVMs match the applet requirements and have enough resources to execute the applet.
A web browser's JavaScript interpreter engine is single thread. The Java Plug-in is capable of managing multiple threads. The Java Plug-in creates a separate worker thread for every applet. Applets themselves may be multi-threaded.
The following figure shows the thread interactions between the JavaScript Interpreter, Java Plug-in, and an applet.
When the JavaScript interpreter is idle, the Java Plug-in executes a JavaScript to Java call on the per applet worker thread (JavaScript Interpreter Not Busy scenario).
When a Java to JavaScript call is in progress and a JavaScript to Java call is made, the latter is executed on the same thread that made the Java to JavaScript call (Round Trip scenario).
When a thread is executing a Java to JavaScript call, another thread wanting to do the same will be blocked till the first thread has received its result and is done (JavaScript Interpreter Busy scenario)
However, Java extension plugin itself is written using NPAPI plugin, the cross-browser API for plugins. Stands for, Netscape Plugin Application Programming Interface. It allowed third-party code in the form of precompiled plugins to be used by the browser to display vendor specific content seamlessly in web pages. Essentially, it lets you call the native binary code from your JavaScript code. But running NPAPI plugin, the code has the full permissions of the current user and has unrestricted access to the local machine. So all in all with NPAPI, security depends on the plugin’s good behaviour and most security considerations
are up to the plugin developer. For example, plugin instances can load
resources from different origins on request of a web page.
Architectural wise, Java needs these privileges to offer the kind of power and control it brings to the table. Java and some versions of Flash and Shockwave still use NPRuntime, and NPAPI needs to be enabled for Java to function correctly in a browser. At the same time many browsers like Chrome consider this (NPAPI plugin) as serious security vulnerability because if the plugin (that uses NPAPI) contains a vulnerability, an attacker might be able to exploit that vulnerability to install malicious software on the user's machine, also sine plugin (java or NPAPI) is exposed directly to web content, making it easier for a malicious web site to manipulate your plugin, which is why it has made it user permission controlled. Another reason why browsers are moving away from this is, NPAPI isn’t supported on mobile devices. Also there are newer problems such as jit spraying http://en.wikipedia.org/wiki/JIT_spraying
Though Chrome has officially stopped NPAPI support, As of Chrome Version 42, an additional configuration step is required to continue using NPAPI plugins. (Could only work till Sept 2015)
In your URL bar, enter:
chrome://flags/#enable-npapi
Click the Enable link for the Enable NPAPI configuration option.
Click the Relaunch button that now appears at the bottom of the configuration page.

Google Chrome Java Workaround

Google has recently announced their intentions to remove client-side Java support from Chrome in the near future. I, a Java developer by nature, have built nearly all of my web-based applications on top of some form of Java.
As such, I am looking for a workaround for Chrome's discontinuation of Java support, without having to rewrite all of my client-side web apps from the ground-up in another language.
Furthermore, I'm searching for a workaround which does not require Chrome's built-in NPAPI workarounds, as I need basic users to be able to continue to use the applets as they are.

The best option I'm aware of is Java Web Start (tutorial), which doesn't run in browser but does allow users to easily run a Java application you serve from a website. Oracle provides some documentation on how to migrate to JWS, but the gist is to simply replace the <applet> tags with a link to a .jnlp file with the same information the <applet> tag had. You may have to tweak Chrome's application defaults as well.
There is also the Google Web Toolkit, which isn't for applets, but does let you write Java that compiles into JavaScript.
If your applets are more integrated into the browser, unfortunately you may not be able to keep using Java. Chromium does offer some alternatives on their NPAPI deprecation page, but they're not pretty. Options include HTML5/WebGL, WebRTC, NaCL, or Chrome Extensions. The Chrome Experiments site is worth browsing if migrating off of Java becomes your best option.
Oracle's official recommendation, however, is to avoid Chrome. That's pretty heavy-handed, and won't work for most website owners, but it's worth mentioning.

Are applets dead?

A long time ago I made an applet, when I tried to a open it few days ago in website and it says that there is a security problem and it can not open it.
I Googled it and saw that I need to register it.
I tried to register it but nothing helped.
Can you explain what could make this problem?
The applet is fine and working when I run it from eclipse.

With recent updates to Java, security is much more strict. Your applet needs to be running the same java version and have a certificate. It's a very strict system...I can't open many java applets myself.
To make it run as an exception, copy the URL that the applet is on. Then open up your Java Control Panel, go to the Security Tab, and at the bottom hit Edit Site List at the bottom. From there, hit Add and paste in your link.
That'll allow it to run as an exception.

tl;dr
Java Applets are gone. You can modify your applet to run as a local app instead.
Today you can build local GUI apps in Java using your choice of three frameworks:
Swing (now in maintenance mode)
JavaFX (actively developed, led by Oracle and Gluon)
SWT (developed by the Eclipse Foundation)
For remote apps written in pure Java but delivered to users as a web app, see Vaadin Flow.
Yes, Java Applets are dead
Oracle has deprecated Java Applet technology, having proven too difficult to integrate securely into web browsers.
All the major web browser makers (Mozilla, Apple, Google, Microsoft, etc.) have phased out support for Java Applets.
Long live Java GUI apps
See white paper by Oracle, Java Client Roadmap Update, 2020-05.
Oracle’s vision for local Java GUI apps is for the developer to deliver a "double-clickable" app bundled with its own JVM slimmed down to include only needed parts. Modern tooling includes jlink and jpackage. Oracle no longer sees Java being generally bundled with operating systems, nor generally being installed by users.
While Java Applets are dead, Swing is still maintained as a required part of every Java implementation. People continue to write Swing apps for use on a local computer. You just cannot run a Swing app within a browser any longer. If you have source code for a Swing-based Applet, you can easily modify it to run as a local Swing app.
Swing’s replacement, JavaFX, is under very active development in the open-source project OpenJFX, a subproject hosted on the OpenJDK project. Releases arrive every six months, around the same time as Java releases.
The Eclipse Foundation continues to offer Standard Widget Toolkit (SWT) as a third platform (besides Swing & JavaFX) for writing Java GUI apps on a local computer.
For an open-source implementation of Java Web Start, see OpenWebStart. Oracle has dropped support for the technology, but others continue to find it a handy way to deliver and launch local Java desktop apps.
If you want to write web apps in pure Java using a Swing/JavaFX style of coding, see Vaadin Flow. Your app executes server-side in a JVM while the user-interface is automatically rendered remotely in the web browser by way of standard web technologies (HTML, CSS, JavaScript/ECMAScript/TypeScript, Web Components).

how to run a java applet in web browser

I have a java SE project or you can say applet, but i want to run this applet in web browser how is it possible?
I need to copy jar file something like this i came to know but what is the possible solution?

This tutorial pretty much covers everything from writing your applet to embedding it on your web page. If you already have your applet done, as it seems, scroll down to "Invoking an applet". Here's the code from the tutorial for a quick solution:
<html>
<title>The Hello, World Applet</title>
<hr>
<applet code="HelloWorldApplet.class" width="320" height="120">
If your browser was Java-enabled, a "Hello, World"
message would appear here.
</applet>
<hr>
</html>

Most modern browsers no longer support Java.
In September 2015, Google decided to remove the support for Java in their Chrome web browser. The Java plugin is based on an old API called Netscape Plugin API that has always had security issues. Google felt that it was time for them to let go of this old technology and make the Web move on to newer and safer technologies like HTML5. When you visit a website or web service that is using Java, you now see a message that says: "The Chrome browser does not support NPAPI plug-ins and therefore will not run all Java content. Switch to a different browser (Internet Explorer or Safari on Mac) to run the Java plug-in."
The Java plug-in for web browsers relies on the cross platform plugin architecture NPAPI, which has been supported by all major web browsers for over a decade. Google's Chrome version 45 (released in September 2015) dropped support for NPAPI, impacting plugins for Silverlight, Java, Facebook Video and other similar NPAPI based plugins. Java applications are now offered though web browsers as either a web start application (which do not interact with the browser once they are launched) or as a Java applet (which might interact with the browser). This change does not affect Web Start applications, it only impacts applets.
If you have problems accessing Java applications using Chrome, Oracle recommends using Internet Explorer or Safari instead.
Developers and System administrators looking for alternative ways to support users of Chrome should see this blog regarding Launching Web Start applications.