Learning the difference between Java and JavaScript

Java versus JavaScript
Java versus JavaScript

The most often confused and interchangeably used terms by newcomers in the software development field are the programming languages Java and JavaScript. Both languages are the most in-demand languages in the market. However, the similarity ends there; the two languages are widely different and have diverse applications and utility.

Let’s begin by highlighting some of the basic differences between the two:

Programming Paradigms

We need to first understand exactly what a paradigm is. Technically, the set of rules, principles, and concepts used to develop a programming language is called its paradigm. Now, a probable and understandable question that comes to mind is: what is the need of a paradigm? Why can’t the same set of rules be applied to all? Every language follows a certain methodology to solve problems. The methodology depends on what the language is designed and designated to do and defines its paradigm. Understanding the paradigm of a language is important to learn its application.

Java is predominantly one of the most famous languages that use an object-oriented programming paradigm. Java is used mostly in application development and server-side development on an enterprise scale. There is a lot of data involved along with functionality, which demanded the way of programming in such a way that equal importance can be given to both data and function. Object-oriented programming is the best option to do so. It binds the data with functions and puts them together in classes to obtain the desired behaviour along with clean coding. Recently, Java has introduced a functional programming paradigm, in the form of lambdas. However, it is a still less-explored style.

On the other hand, JavaScript is a multi-paradigm language. It can be used in both the object-oriented paradigm and the functional paradigm. Since the use of JavaScript is quite flexible, you can experiment and decide upon the paradigm. If it involves a large amount of data, you can go with object-oriented methodology. If it is more on the functional side, opt for a functional paradigm.

SYNTAX AND FEATURES

By using an analogy, we can attempt to understand what exactly syntax and features mean for a programming language. Imagine the time when you started learning the English alphabet: you were taught exactly how ‘A’ is spelt and written. You practised writing it and the other letters singularly and gradually, with the help of syntax and paradigm laid out for the English language, today you’re able to write sentences and articulate well in the written word. In a similar manner, when you start with a programming language you need to understand certain rules of writing the code in order to build meaningful programs and software, thus making it the syntax.

Features can be seen as the abilities that are inbuilt in the language to allow you to build large scale applications utilising them.

In the following sections, we look at some of the features of Java and JavaScript to understand the difference between them:

Type Checking

Type checking is used to know the data type of the objects or variables in runtime.

In JavaScript, typeof is used to do type checking.

Inheritance

Inheritance is a classic feature of object-oriented programming. It establishes the relation between dependent classes where the child class inherits the data or the function from the parent class. It solves the problem of an explicit definition of functions for different child classes.

To understand the concept, let’s see an example , how it is used in java:

Function Overloading

Function overloading is a striking feature in Java that allows a class to have multiple functions of the same name with different types and number arguments. This saves you from memorising multiple function names while programming, thereby making the code clean and efficient. However, on the other hand, although JavaScript supports an object-oriented programming paradigm, it has no concept of function overloading.

Multithreading

To understand multithreading, let’s first understand the concept of a thread. A thread is an independent component of a whole application that can be executed. Java provides built-in support for multithreading which helps it execute multiple threads at the same time, thereby reducing the time of execution.

JavaScript does not support multithreading because the JavaScript interpreter is a single thread on the web browser. Here, multithreading can create concurrency issues.

Closures

The closure is another important concept in JavaScript. Closure requires that, for nested functions, the inner function must have access to the variables of the outer function. The reference of the outer function variable is shared between both the functions, thereby allowing you to make private variables in the function.

Java doesn’t support Closures. It has inheritance methods and lambda expressions instead.

Compilation and Execution

Java uses a compiler to execute its program. The source code goes through the compiler so that it can be converted into byte code, which is understandable by the machine. Once converted, the machine can execute the program.

JavaScript programs don’t need to go through any compiler. Because it is an interpretable language, it goes directly to the interpreter of the browser, where it is executed line by line.

Conclusion

If you’ve read so far, we hope that we’ve been able to help you establish the difference between Java and JavaScript, conceptually as well as practically. If you’re on your path to learning either or both, these are powerful skills to have up your sleeve which can be used in various aspects. Once you identify your programming needs, you should easily be able to choose the language you want to work with. 

We’d like to conclude the difference between the two with the famous words by Baruch Sadogursky, spoken in an interview: Java is to JavaScript what ham is to a hamster.

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