What are Java and JavaScript?

codeworks what is java

What is Java? Java is a general-purpose programming language designed with a specific mantra in mind: “write once, run anywhere.” (coined in 1995 by Sun Microsystems) Java applications are compiled into bytecode that can run on implementations of the Java Virtual Machine (JVM). The JVM helps bridge the gap between the source code and the 1s and 0s that the computer understands. Any computer with the JVM installed can run Java. In web development, Java is most prominent as a server language and is the chosen programming language for mobile apps on the Android platform. It also maintains a decent presence on the front end as a Java applet, although this is falling out of favor due to security concerns.

What is JavaScript? Alongside HTML and CSS, JavaScript (standardized as ECMAScript) is considered one of the three main core components of the web. Used by the most websites, JavaScript is a scripting language that typically runs in the browser, making web pages dynamic and interactive. Today, JavaScript is also rapidly growing as a server-side technology since the launch of Node.js.

Java vs. JavaScript: Key Similarities Despite their differences, there are some top-level similarities worth considering, especially when looking at web development in comparing Java with JavaScript. Object-Oriented Programming (OOP): Both of these languages require developers to code in terms of objects and their relationships to one another. This extends to both languages having access to techniques such as inheritance, encapsulation, and polymorphism. Front-end Development: Both languages can be used in aspects of front-end development. JavaScript can be embedded directly into HTML, implemented as a framework or library; Java can be used as a Java applet. Back-end Development: Both languages can be utilized on the server-side. Java has long been used to power back-end technologies such as Apache, JBoss, and WebSphere. Node.js has become a launching pad for JavaScript-powered servers.

Java vs. JavaScript: Major Differences

It’s important to remember that Java and JavaScript have evolved to serve completely different purposes. Java was designed as a general-purpose programming language for building standalone applications, while JavaScript is a scripting language specifically built to interact with web technologies, namely HTML. When Java was released by Sun in 1991, it was initially used to program home electronics like VCRs. JavaScript was introduced to be used alongside Java as a client-side scripting language that could run in the browser without needing to be compiled. Let’s take a closer look at some of the major differences between these two languages.

Compiled vs. Interpreted: Java is considered a compiled programming language. JavaScript is considered an interpreted scripting language. The difference lies in the implementation: Java is compiled into bytecode and runs on a virtual machine, while JavaScript can be interpreted directly by a web browser in the syntax it is written (although it is usually minified in practice).

Static vs Dynamic Type Checking: Java uses static type checking, where the type of a variable is checked during compilation. The programmer must specify the type (integer, double, string, etc.) for all variables they create. JavaScript, like most scripting languages, uses dynamic typing, where type safety is verified at runtime. It is not required for a programmer to specify the type of any variable they create. There are many pros and cons to these two paradigms, but the main advantage of static type checking is that type errors are caught early in development, and because the compiler knows exactly what data types are used, the code usually executes faster or uses less memory. The main advantage of dynamic type checking is the programmer’s productivity – you are free to assign types as you wish.

Concurrency: The ability to handle the execution of multiple instruction sequences simultaneously is handled very differently between Java and JavaScript. Java uses multiple threads to perform tasks in parallel. JavaScript, especially as it exists as Node.js in server-side applications, manages concurrency on a main execution thread via a queue system known as the event loop and a forking system called Node Clustering. For most use cases, both methods work well, but Java is generally faster because thread-to-thread communication is much quicker than interprocess communication (IPC).

Class-based vs Prototype-based: Java follows class-based inheritance – a top-down, hierarchical, class-based relationship where properties are defined in a class and inherited by an instance of that class (one of its members). In JavaScript, inheritance is prototypical – all objects can inherit directly from other objects. Hierarchy in JavaScript is achieved by assigning an object as a prototype with a constructor function.

Should I Use JavaScript or Java for My Next Project?

Like with any language, the choice really comes down to what you are trying to build and the resources you have at your disposal. JavaScript remains very much a web technology, while Java is a general-purpose language that can build anything. You should consider Java if your project involves:

  • Android apps
  • Enterprise software
  • Scientific computing
  • Big Data analytics
  • General hardware programming
  • Server-Side Technologies like Apache, JBoss, Geronimo, GlassFish, etc.

You should consider JavaScript if your project involves:

  • Dynamic single-page applications (SPA)
  • Front-End technologies like jQuery, AngularJS, Backbone.js, Ember.js, ReactJS etc.
  • Server-Side technologies like Node.js, MongoDB, Express.js, etc.
  • Mobile app development through PhoneGap, React Native, etc.

Keep in mind that neither list is comprehensive; these are only intended as a starting point to help you get a sense of what you can expect and which keywords you might use to assess the best language for your needs.

At Codeworks we offer a free intro course to Javascript, so if you feel the itch to test your knowledge feel free to give it a go.

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