Learn Java. Java is a popular programming language. Java is used to develop mobile apps, web apps, desktop apps, games and much more. Start learning Java now »

What is Java? Java is a popular programming language, created in 1995. It is owned by Oracle, and more than 3 billion devices run Java. It is used for: Mobile applications (specially Android apps) Desktop applications; Web applications; Web servers and application servers; Games; Database connection; And much, much more!

2024年8月21日 · W3Schools' Java Editor. When learning Java at W3Schools.com, you can use our "Try it Yourself" tool, which shows both the code and the result. It is used to write, run, and test code right in your browser:

Java Classes/Objects. Java is an object-oriented programming language. Everything in Java is associated with classes and objects, along with its attributes and methods. For example: in real life, a car is an object. The car has attributes, such as weight and color, and methods, such as drive and brake.

Java Syntax. In the previous chapter, we created a Java file called Main.java, and we used the following code to print "Hello World" to the screen:

OOP helps to keep the Java code DRY "Don't Repeat Yourself", and makes the code easier to maintain, modify and debug; OOP makes it possible to create full reusable applications with less code and shorter development time; Tip: The "Don't Repeat Yourself" (DRY) principle is about reducing the repetition of code. You should extract out the codes ...

Well organized and easy to understand Web building tutorials with lots of examples of how to use HTML, CSS, JavaScript, SQL, Python, PHP, Bootstrap, Java, XML and more.

Well organized and easy to understand Web building tutorials with lots of examples of how to use HTML, CSS, JavaScript, SQL, Python, PHP, Bootstrap, Java, XML and more.

W3Schools offers a wide range of services and products for beginners and professionals, helping millions of people everyday to learn and master new skills. Free Tutorials

W3Schools maintains a complete JavaScript reference, including all HTML and browser objects. The reference contains examples for all properties, methods and events, and is continuously updated according to the latest web standards.