How can I practice Java online?

How to run Java code in browser?

This is something a friend asked me a while back, and I never answered it since.

If there's anyone who actually wants to, feel free to shoot down my answer in the comments. But then, that person may be more willing to read up on java than I am.

What are you trying to do? How to run Java code in a browser? - I want to be able to display some Java application in the browser window. How to do this? - And once I can run the application, how to deploy and host the code? I'm not the author of the question, though. I just wanted to make it available, in case there are more useful answers out there.

UPDATE: You can now get a version of the java code running in your browser! Read my post about it. First of all, what do you mean by "running" a program in a browser window? All your browser does is make the data the web page generates available as input/output to your Java code. Your program then manipulates the data on the fly, and then sends the manipulated data to the browser again. So that means you're actually sending data from your program directly to the browser, rather than just to a Java applet.

The two main types of browsers for running Java in are the Netscape Navigator series and the Google Chrome series. You can read the details about them here. (This is what I used to get my version up.)

So basically you need to find a Java viewer, the name given to the actual applet that runs the code. This will usually be called something like "Mozilla Sun Plugin Viewer".

Download this one if you're using Microsoft Windows. It should work okay on any version of MS Internet Explorer or Netscape Navigator, though I only tested it on IE4.0 and Netscape 3.02. (Though it might work on some other version). Download the .zip file from here. It contains an applet called mozjpeg.jar which needs to be added to the plugin list. For MS Internet Explorer that should be on the Plug-Ins tab, and in Netscape it's either under the Preferences / Extensions area, or in the Netscape Help/FAQ's. (For IE4.0 the plug-in is called sun.

Where can I test my Java code online?

It's always a good idea to write unit tests for any code you write.

But for Java, there are several online testing sites that you can use to test the following: WebSocket Chat - Uses the WebSocket protocol to create a live chat app on the browser. JavaScript Testing Tool - Just a plain old web site that allows you to write, compile, and run your JavaScript with a JVM. You will need to install a browser if you want to use this service.

JavaScript-jmeter - Another tool to do dynamic JavaScript load testing using an Apache JMeter test plan.

Can I write Java code online?

Can I write a program in a text editor, and then use some program to make it work online? For example, I have a game that I have made, and I want to put it online. But I'm afraid that people might steal my code, and copy it onto their own servers and ruin the game for me. Is there a way to protect my code so that it's safe? I've tried looking at ways of doing this, but they seem to be for old versions of Java. No, you cannot write code online. Java is a proprietary language. It does not have an open source community.

You can do research and maybe even write a few programs online, but it's not safe. There are no open source compilers. The closest thing you have to a free compiler is a free IDE. You can use Eclipse and its Java compiler. Also, you could look into Java byte code obfuscation. It is impossible to protect your code from being stolen, because it is always possible to write your own implementation of the Java virtual machine. The only way you can protect your code is to make it so difficult to write your own implementation that you will never be able to do so.

In Java, this is accomplished through the use of a virtual machine. This means that your code is run by a separate interpreter which handles the details of the Java language, such as memory management, variable types, class definitions, etc.

If you want to make it impossible for someone else to write a VM for your Java code, you need to make it so that it is not possible to understand your code without knowing how the VM works. This would be similar to making it impossible to understand English without knowing how a computer works.

This is quite possible. There are many programming languages which, as far as I know, cannot be understood without knowing how to program.

Of course you can, but you should use a tool which can obfuscate your code. If you are using Eclipse, you can use a plugin like javapackageoptimizer.