How to Build an Online Java Compiler

Coding can be a tricky and lengthy process, which makes it simple to disregard compilation errors that can affect the quality of the result. Therefore, development tools have been introduced to help ease the stress of the process and enhance the quality of the code.

These tools are accessible online and as desktop applications to enhance developer productivity. Java is considered one of the simplest programming languages to implement and use.

However, errors are inevitable. Online Java developer tools, including an IDE, code editor, compiler, and interpreter, are available to help avert mistakes. This article will focus on how to build an online Java Compiler for developers and help them with the process.

Do you wish to delve into Java programming without first setting up your computer? If so, you’ve come to the right places. We’ll also look at different online Java tools such as Java Compiler online that allow you to modify, design, debug, and run java code, among other things.

An online java compiler’s functionality can range from a simple converter that converts .java files to .class files to a comprehensive cloud-based online java IDE that can be used to administer java projects.

What is Java Compiler?

Java is a strongly typed language, which implies variable should hold the right type of data. In a strongly typed language, a variable can not hold incorrect data type.

This is a safety feature very well incorporated in Java Programming Language. Java compiler handles scrutinizing the variables for any negligence in data-type holding. A few exceptions may occur during run-time, which is imperative for the dynamic binding feature of Java.

As Java program runs, it may introduce new objects that were not existing before, thus to have some flexibility, some exceptions are allowed in data-type that a variable can hold.

Java Compiler set a filter for those sections of code that will not compile ever other than the comments. Compiler does not parse the comments and leaves the way it is. Java code backs three types of comments within Program.

• /* COMMENT HERE */
• /** DOCUMENTATION COMMENT HERE */
• // COMMENT HERE

Java Compiler ignores anything that sits between /* and */ or /** and */ or after //.

It handles strictly checking any syntax violation and is devised to be a bytecode compiler, out of an actual program file, it creates a class file constructed purely in bytecode.

Considered to be the first stage of security, Java Compiler is the first line of defense, where checking for incorrect data-type in the variable is checked.

A wrong data-type can harm the program significantly and outside it. Additionally, the compiler checks if any piece of code is trying to enforce restricted piece of code like private class.

It restrains unauthorized access to code, class or critical data. Java Compiler renders bytecodes/class file that are architecturally and platform neutral and doesn’t require JVM (Java Virtual Machine) to execute and it will function in any architecture or platform or device.

Difference Between Online and Offline IDE

Offline IDEs

There are many offline IDEs that developers use in order to stay more productive, to comprehend, and to be more productive at work. Eclipse 40 is just not a Java editor. Its significant benefits are code completion by tabbing method, which cuts down time while writing documentation.

It comes with a built-in syntax check to resolve any mistyped words during coding a project. The qualities we expect of an IDE are their templates, integration with different SCMSs, code completion, and integration with build systems.

The IDE’s code formatting and cleanup tools are compelling and its build system works well and intuitively. Furthermore, it is equipped with a find and replace function, variables and classes of a specific project and a refactoring function.

A free intuitive editor, NetBeans 32 does it all. It has an easy “Swing GUI” design tool to develop user interfaces by dragging and dropping components, for example textboxes or buttons. One shortcoming is that, considering all of its features, loading times rise and more memory is being utilized, compared to other IDEs.

IntelliJ IDEA 7 is the most effective offline editor, but it’s not free. It is quicker than most editors, yet it has several issues. One major disadvantage is that it takes up too much memory.

BlueJ 10 is an easy editor mostly employed to teach java and object-oriented programming. The major advantage of this editor compared to other IDEs is that it does not require a primary method to run the program.

Online IDEs

An online IDE, CodeRun Studio 64 lets you design web applications. It lets you to run and test code online and lets you use it for a 14-day trial period before you have to pay to continue to use it.

During the trial period, the “save” function is also disabled, which makes it difficult to use this program. Cloud9 IDE 39 Cloud9 IDE is another open source, version 3.0 and, onwards, online integrated development environment.

It backs several programming languages, such as JavaScript, PHP, Ruby, Perl, Python, with Node.js, and Go. It allows programmers to get started with coding instantly with preset workspaces, cooperate with their peers utilizing collaborative coding features, and web development features such as live preview (“WYSIWYG” or “What You See Is What You Get”) and browser compatibility testing. It is drafted almost entirely in JavaScript, and makes use of Node.js on the back end. The editor component utilizes Ace.

How to build an Online Java Compiler

It is a tedious task to devise a compiler for your project. In this article, we will show you the ways to create your own interesting simple online compiler in ReactJs with the help of Judge0 in less than 200 lines of Code.

A scalable and robust open-source online code execution system, Judge0 is can design a variety of applications ranging from competitive programming platforms, online code editors, educational and recruitment platforms, etc.

Judge0 supports over 50+ languages and if you wish to add more language support, you can go through the Official documentation and incorporate any language as per your need. We will design a compiler that supports 4 languages, namely C/C++/Python and Java.

It is advised that you should follow the content as it is and follow every step meticulously. Designing an online code editor and compiler can appear to be too complex, but we can break it down into two pieces.

• API running on the backend server, which will, as input, take up a piece of code and language and output the answer after running the code on the server
• Frontend code editor, we can select the language and edit and change the code here. Post which, we can make a post request to the backend API and show output on the website.

Table Content :

• Get Your API key
• Design React App
• Building Your Components

Steps to follow:

- Get your API key :

Get your API key for free at https://rapidapi.com/judge0-official/api/judge0-ce/

- Create Your React App :

Follow the below steps to create your React project

npx create-react-app my-app

cd my-app

npm start

- Creating Components :

Let’s go and first create a Compiler folder. This folder will keep files related to the Compiler.

Create a file named: Compiler.js in Compiler

Let us understand the code in a step by step :

• We have made use of 4 states.
• The source code provide by the user, input handles it.
• Output derived from the judge0 compiler, post the submission of code is handled by coutput
• language_id manages the Language we wish to compile our source code in
• user_input deals with the stdin input given by the user.
• The first fetch request Create your submission to the judge0 compiler and return a unique token.
• We get back the result/output of our submitted code with the help of the unique token in our second fetch request.
• We have some JSX inside the render method.

Note: The above file makes use of Font Awesome and Bootstrap instances, so make sure you enter their cdn link in the index.js file below the public folder.

Explanation

Importing the package ‘Component’ from react and acss file Compiler.css

Inheriting the Component class from Compiler and initializing it’s state using a constructor.

The next task is to capture the events that has occurred and its target value is recorded. Similarly, any user input is also recorded as an user event.

Now, the main task is to get the language_id of the programming language that we want our compiler to recognize.
In this case, it’s Java and the language_Id is 62.

Next, using the REST call, we post the above information using the API Key

On submission of the above details of the compiler, the response is awaited i.e. whether our entered details have been accepted or not.

The first fetch request createsour submission to the judge0 compiler and returns a unique token.

If the submission is accepted, then using the GET method of the REST call we get the details.

We get back the result/output of our submitted code with the help of the unique token in our second fetch request.

Next, we initiate the React app and specify its contents as JSON because the output of the previous GET call gives us results in JSON format.
The solution from the compiler is then displayed.
If any error is detected by the compiler, then it throws an error.

Next a form is created, to allow the user making the compiler to make various entries and selections about the compiler he/she is about to create.
This form entries are stored in a function render() which is called whenever a new compiler details are to be accepted.
We have some JSX inside the render method.

The Compiler functionality part is over here. We have incorporated the support of execution for C/C++/Python and Java. Let’s Create a new file named Compiler.css under compiler folder.

Thus, we have created a simple online compiler in react using judge0. YOu can also run your program to build a compiler from this source.

Conclusion

The world is moving towards technology, and everyone seeks to figure out at least the basics of programming, regardless of their field. Building up the entire system to run some snippets might be time-consuming and useless for many people.

As a result, online ready-to-use compilers and editors are quite useful. Particularly if you don’t belong from a programming background. In any event, the traditional notion of setting up local workstations or servers is no longer preferred, and online cloud-based development tools are growing into the norm.

InterviewBit’s online compiler, mentioned in this article, is of the best and we really hope that one of them will be the right fit for you.