Java vs JavaScript - A Detailed Comparison

About Java and JavaScript

What is Java?

Java is a high-level, object-oriented programming language that was created by Sun Microsystems in 1995 and has since become a widely used language in the programming world. Java can run on any device that has a Java Virtual Machine (JVM) installed, making it an ideal choice for developers who want to create applications that can be used across multiple platforms and devices.

Java is a popular programming language because of its ease to use, reliability, and versatility. Developers all around the world use it to make different types of computer programs, ranging from simple to complex. It follows an object-oriented programming model which makes it easier and faster to build software. Moreover, Java comes with many useful libraries and tools that can help developers be more productive and efficient.

There is huge community support for Java. People love to contribute, help and collaborate. Over the years, Java has introduced new features and capabilities. Its continued improvements have made it an ideal choice for building complex applications and many companies look to hire Java developers.

What is JavaScript?

We generally use HTML to structure the webpage and CSS to add styling to it but that is only the static web page where users can't interact. That is where JavaScript language comes into play.

JavaScript is a lightweight programming language that is cross-platform, interpreted, and object-oriented. Developers use JavaScript to design interactive and dynamic web pages. JavaScript supports both client-side and server-side programming. JavaScript is one of the most popular programming languages because it is highly versatile. It allows us to control multimedia, animate pictures, and do a variety of other things.

There are two methods for adding JavaScript code into an HTML web page: internally and externally. In the Internal  JavaScript method, <script> tag is used within the body of HTML to add all the JavaScript code. External JavaScript, on the other hand, requires storing the code in a separate .js file and then retrieving it within the HTML page. While working on large projects, developers frequently use this technique to keep the code structure organized.

Key Features

Java - Key Features

Object-oriented programming: Java is a pure object-oriented programming (OOP) language. Everything in Java is an object, including the basic data types, and it follows the principles of OOP like inheritance, abstraction, polymorphism, and encapsulation.

Platform independence: Java programs can run on many different platforms like Windows, Linux, and MacOS, without having to change the code. To do this, the code is first turned into a special type of code called bytecode, which can run on any computer that has a program called the Java Virtual Machine (JVM).

Multi-threading: Java supports the concept of multi-threading, which enables it to perform many tasks at once. This feature is extremely helpful for building applications that need to handle multiple tasks simultaneously.

Security: Java is known for its security features. It has a strong security framework that includes a security manager, digital signatures, and policy file making it a very secure programming language.

Scalability: Java is easily scalable, meaning it can handle large applications and workloads without issues. This is due to its ability to run on multiple platforms, automatic memory management, and support for multi-threading.

Automatic memory management: Java comes with a built-in garbage collector that takes care of memory allocation and deallocation automatically. This means developers don't need to worry about managing memory manually, which helps to reduce the risk of memory-related issues like crashes and memory leaks.

Rich API library: Java has a wide range of APIs that offer pre-built functionality for tasks such as networking, database access, and file handling.

JavaScript - Key Features

Cross-platform: JavaScript language is supported by various operating systems including Windows, macOS, and Linux. It is built into Netscape 2.0 and greater, and runs on all platforms which support Netscape.

Light-weight: Since JavaScript is not a compiled language, there is no prior byte-code conversion. However, it does adhere to a model known as Just-In-Time (JIT) Compilation. Hence, just before it executes, it is transformed to bytecode. Because of this, JS is a lightweight programming language. JavaScript can be executed on even less powerful machines.

Interpreted: As discussed above, JavaScript is not a compiled language but it's rather an interpreted language just like Python and Ruby. The source code of JavaScript is interpreted by the browser, line by line and is then executed.

Browser support: JavaScript is supported by almost every web browser including Chrome, Firefox, Safari etc.

Case sensitive: JavaScript is a case-sensitive language where all variables, function names and other identifiers must follow consistent capitalisation of letters.

Object oriented: JavaScript is a prototype based Object Oriented programming language. Data types like Arrays, Functions, etc. inherit properties of the object prototype.

Scripting language: JavaScript is a lightweight scripting language designed for client-side processing on the browser. It manages the web pages displayed to the user and its associated processing, such as cookies, sessions, and local storage, on the client's machine (browser).

Dynamically typed: Type checks (whether string or number) take place during run-time which makes JavaScript dynamically typed language. In JS, we don't need to clearly state upfront what kind of data will be kept in a variable. For instance, when we define var "num", "num" can now hold a string or an integer.

Performance Comparison

Java Performance

Java is a popular programming language for applications that require high performance. Java is well-known for its fast execution speed and smooth performance. Performance metrics for Java include memory usage, execution speed, and scalability.

Java's excellent performance is often attributed to its fast execution speed and smooth performance. This is due to several factors, including its Just-In-Time (JIT) compiler, which optimizes code at runtime, and its multi-threading capabilities, which allow for efficient parallel processing.

Multi-threading is a key component in Java's performance. It allows multiple threads to run concurrently within a single program, which is especially useful for applications that need to handle multiple tasks simultaneously.

Java's automatic memory management system also contributes to its smooth performance. The garbage collector is a critical component of this system, that automatically deallocates memory that is no longer in need. This reduces the risk of memory leaks and crashes and further improves the program's performance.

Overall, Java's performance is impressive because of its Just-In-Time (JIT) compiler, automatic memory management, and multi-threading capabilities. These features work together to make Java a highly performant programming language suitable for a wide range of applications.

JavaScript Performance

JavaScript is a widely used programming language for creating web applications and interactive experiences and many firms look to hire JavaScript developers. Its performance has improved considerably over the years, thanks to enhancements in web browser speed, hardware, and JavaScript language features. The faster and more efficient web browsers have allowed JavaScript to perform better, which means developers can now build more complex and interactive applications that run more smoothly and respond more quickly.

Modern JavaScript engines, like V8 and SpiderMonkey, can compile and execute code at incredibly fast speeds. This makes it easier for developers to create highly responsive applications that users can enjoy without delays or lags.

Another critical factor that affects JavaScript performance is the smoothness of the user interface. To achieve this, developers need to minimize the time taken for JavaScript to render and update the user interface, as well as optimize the use of memory and other system resources. Techniques like lazy loading, code splitting, and caching can help to reduce the amount of JavaScript that needs to be loaded and executed by the browser, ensuring a smoother and more responsive user experience.

JavaScript's performance has significantly improved and is expected to continue doing so as web technologies and hardware advance further in the future.

Popularity over the years

Java

Java has remained a popular programming language for many years and its popularity has been consistently growing. According to the TIOBE Index, which measures programming language popularity, Java has been one of the top languages for decades. Additionally, Java is the second most popular language on GitHub, a popular code repository as of April 2023.

Java's popularity has been boosted in recent years due to the rising demand for mobile app development. Android, the most widely used mobile operating system, is built on Java. Therefore, many developers have turned to Java to create Android apps, contributing to its increasing popularity.

JavaScript

Over 1.8 billion websites exist worldwide, and 95% of them use JavaScript. According to Github's 2020 Octoverse Report, JavaScript is by far the most popular language.

The basis for JavaScript's success is its origin tale. Its original name was Mocha, followed by LiveScript and then Javascript. The story starts in December of 1995 at the Netscape headquarters, where Brendan Eich participates in a ten-day coding sprint and comes out with a new language. Because of a license deal between Netscape and Sun (the company that owned Java), the language was renamed to Javascript and particularly "Java" script because Java was the most popular language at that time and this would help in Javascript's marketing.

While JavaScript has earned the title of "The Language of the Browser," its destiny changed in 2009 with the introduction of Node.JS, a runtime environment that allows JavaScript code to be executed outside of a web browser. Because Node.JS represents the idea of "JavaScript everywhere" paradigm, JavaScript's popularity has consequently increased.

Due to JavaScript's popularity, a number of libraries and frameworks have been developed, which have improved the effectiveness and efficiency of application development. React JS, jQuery, D3.JS, and other libraries are now used in the majority of apps all over the globe. Large apps can be built with the optimal performance of frameworks like Angular, Ember JS, and Vue JS. According to Stackoverflow, JavaScript has one of the largest communities amongst the programming languages.

Advantages and Disadvantages

Advantages of Java

High Performance: Java is known for its fast execution speed and smooth performance, thanks to its JIT compiler, automatic memory management, and multithreading capabilities.

Large Community and Support: Java has a large community of developers who provide support and resources for learning and development.

Platform Independence: Java is an extremely versatile programming language due to its "Write Once, Run Anywhere" principle, which enables it to run on any platform without requiring modifications.

Mobile App Development: Java is widely used for developing mobile applications, especially on Android devices, due to its platform independence, scalability, and security.

Robust and Reliable: Java is a robust and reliable language due to its strict type-checking feature, which identifies errors during the compilation process, and reduces the chances of errors occurring during the runtime.

Disadvantages of Java

Memory: Java programs utilize more memory because they run on the Java Virtual Machine.

Garbage collection: In Java, programmers cannot control the garbage collection process and do not have access to functions such as delete() or free().

Low-level programming: Java does not support low-level programming concepts, such as the use of pointers.

Cost: Hardware cost increases due to the higher memory and processing requirements.

Advantages of JavaScript

Less server load: JavaScript runs on the client-side and hence, the requests sent to the server get reduced. User input is validated before the request is sent to the server and hence, it saves server traffic which reduces the load on the server.

Rich interface: JavaScript's rich interface capabilities allow for dynamic and interactive web pages, with features such as animations, user input validation, and real-time updates without requiring a page refresh. This makes for a more engaging and seamless user experience on the web.

Increased interactivity: By allowing developers to manipulate HTML and CSS elements in real-time, JS can enhance the user experience by providing increased interactivity, dynamic content updates, and seamless page transitions.

Speed: JS runs on the client side without the need for outside resources and third party apps which makes it a very fast language.

Versatility: JavaScript is a highly versatile programming language that can be used for both front-end and back-end development, as well as for building mobile and desktop applications. Its flexibility and vast ecosystem of libraries and frameworks make it a popular choice for developers across various domains.

Updates: In order to maintain JavaScript's relevance within the industry, the development team and ECMA International regularly update and build new frameworks and libraries.

Disadvantages of JavaScript

Browser compatibility: JavaScript can behave differently in different browsers resulting in different outputs, which can cause compatibility issues.

Multi-threading or Multiprocessing: JS doesn't support multi-threading or multi-processing.

Debugging: Debugging JavaScript can be challenging due to its loose typing and dynamic nature, making it more prone to errors.

Client-side security: JavaScript is executed on the client-side, which means that it can be exploited by attackers to carry out malicious activities.

Use Cases

Java - Use Cases

Object-oriented programming: Java is a pure object-oriented programming (OOP) language. Everything in Java is an object, including the basic data types, and it follows the principles of OOP like inheritance, abstraction, polymorphism, and encapsulation.

Platform independence: Java programs can run on many different platforms like Windows, Linux, and MacOS, without having to change the code. To do this, the code is first turned into a special type of code called bytecode, which can run on any computer that has a program called the Java Virtual Machine (JVM).

Multi-threading: Java supports the concept of multi-threading, which enables it to perform many tasks at once. This feature is extremely helpful for building applications that need to handle multiple tasks simultaneously.

Security: Java is known for its security features. It has a strong security framework that includes a security manager, digital signatures, and policy file making it a very secure programming language.

Scalability: Java is easily scalable, meaning it can handle large applications and workloads without issues. This is due to its ability to run on multiple platforms, automatic memory management, and support for multi-threading.

Automatic memory management: Java comes with a built-in garbage collector that takes care of memory allocation and deallocation automatically. This means developers don't need to worry about managing memory manually, which helps to reduce the risk of memory-related issues like crashes and memory leaks.

Rich API library: Java has a wide range of APIs that offer pre-built functionality for tasks such as networking, database access, and file handling.

JavaScript - Use Cases

Cross-platform: JavaScript language is supported by various operating systems including Windows, macOS, and Linux. It is built into Netscape 2.0 and greater, and runs on all platforms which support Netscape.

Light-weight: Since JavaScript is not a compiled language, there is no prior byte-code conversion. However, it does adhere to a model known as Just-In-Time (JIT) Compilation. Hence, just before it executes, it is transformed to bytecode. Because of this, JS is a lightweight programming language. JavaScript can be executed on even less powerful machines.

Interpreted: As discussed above, JavaScript is not a compiled language but it's rather an interpreted language just like Python and Ruby. The source code of JavaScript is interpreted by the browser, line by line and is then executed.

Browser support: JavaScript is supported by almost every web browser including Chrome, Firefox, Safari etc.

Case sensitive: JavaScript is a case-sensitive language where all variables, function names and other identifiers must follow consistent capitalisation of letters.

Object oriented: JavaScript is a prototype based Object Oriented programming language. Data types like Arrays, Functions, etc. inherit properties of the object prototype.

Scripting language: JavaScript is a lightweight scripting language designed for client-side processing on the browser. It manages the web pages displayed to the user and its associated processing, such as cookies, sessions, and local storage, on the client's machine (browser).

Dynamically typed: Type checks (whether string or number) take place during run-time which makes JavaScript dynamically typed language. In JS, we don't need to clearly state upfront what kind of data will be kept in a variable. For instance, when we define var "num", "num" can now hold a string or an integer.

Which is better - Java or JavaScript

Both Java and JavaScript are powerful technologies with unique strengths and weaknesses. Java is best suited for building robust, enterprise-level applications, while JavaScript is ideal for developing interactive, user-friendly web interfaces. Both technologies are widely used in the industry and offer numerous career opportunities for developers.

Java and JavaScript are largely independent of each other. While they can be used together to build full-stack applications, they serve different purposes and are not reliant on one another to function. However, knowledge of both technologies can be beneficial for developers, as it allows for greater versatility and the ability to tackle a wider range of projects. Ultimately, the choice between Java and JS depends on the specific requirements and goals of the project.