Java is a class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let application developers write once, run anywhere (WORA) meaning that compiled Java code can run on all platforms that support Java without the need for recompilation. Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of the underlying computer architecture. The Java runtime provides dynamic capabilities such as reflection and runtime code modification) that are typically not available in traditional compiled languages. As of 2019, Java was one of the most popular programming languages in use according to GitHub particularly for client-server web applications, with a reported 9 million developers.

Following are the notable features of Java:

1. Object Oriented:
In Java, everything is an Object. Java can be easily extended since it is based on the Object model.
2. Platform Independent:
Unlike many other programming languages including C and C++, when Java is compiled, it is not compiled into platform specific machine, rather into platform-independent byte code. This byte code is distributed over the web and interpreted by the Virtual Machine (JVM) on whichever platform it is being run on.
3. Simple:
Java is designed to be easy to learn. If you understand the basic concept of OOP Java, it would be easy to master.
4. Multithreaded:
With Java's multithreaded feature it is possible to write programs that can perform many tasks simultaneously. This design feature allows the developers to construct interactive applications that can run smoothly.
5. Interpreted
Java byte code is translated on the fly to native machine instructions and is not stored anywhere. The development process is more rapid and analytical since the linking is an incremental and light-weight process.

List of top 5 best websites for learning java online for beginners, expert coders:-

• W3 Schools

  W3Schools is an educational website for learning coding online. Content includes tutorials and references relating to HTML, CSS, JavaScript, JSON, PHP, Python, AngularJS, React.js, SQL, Bootstrap, Sass, Node.js, jQuery, XQuery, AJAX, XML, Active Server Pages, R, Raspberry Pi, C++, C# and Java. It is free and easiest way to learn.

  
• CodeAcademy

  The next website on our list is the Code Academy. Code Academy is a free, online learning center that provides tutorials for all things programming. It contains lessons on almost every programming language and also on a variety of other topics. The best part about the website is that it allows the learners to write code directly on the browser. This will allow them to read and implement the codes at the same time. This will be very useful to the learners as they don’t have to setup a development environment for practice exercises.

  
• Udemy

  Udemy is the next website on our list of 5 Best Websites. It is one of the most popular online platforms for learning any programming language including Java. The Java Programming for Beginners course of the Udemy is best for every programmer who needs to build a sound foundation in Java. The courses on Udemy comes together with working files that are split into 14 different sections. The courses on Udemy are made especially for the beginners for high-quality Java training.

  
• Tutorialspoint

  Tutorial Point is the next website on our list of 5 Best websites for learning Python. TutorialsPoint is very much similar to the Code Academy. It also offers free tutorials and also offers learners the option to test their codes directly in a browser window. The website also offers one of the most comprehensive tutorials for beginners programmers. TutorialsPoint will take the learners from the basic and beginner stage of the language to the expert level tasks. The website also includes tutorials about how to set up a Python development environment and writing basic syntax. TutorialsPoint also includes tutorials about working with variables, operators and loops, and much more.

  
• Github

  Github is the next website on our list of 5 Best Websites. Most of the programmers may be knowing that they can host their projects free on the website. However, very few of them may be knowing that it is an excellent resource for learning about Java libraries and frameworks. If the programmer wants to learn about a particular framework, they just have to search for it on the website. The programmer will find various open source projects that will help them to understand the framework. etc.